JPH02179663A - Developing device - Google Patents

Abstract

PURPOSE:To rapidly move a developing part without the leakage of replenished developer and to form a distinct image with a simple constitution by making a developer carrier contact with or separate from a latent image carrier by the use of an eccentric rotating cam, etc., and controlling the impressing of bias voltage. CONSTITUTION:The developing part 2 having the developing roller 6 being the developer carrier is provided so that it can freely reciprocate, retreat and move through the turning eccentric cam 3 and a spring 8 for returning. At the time of developing, the roller 6 approximates to or contacts with the photosensitive drum 5 being the latent image carrier. By interlocking with the contact/uncontact of the roller 6, the developing bias is impressed on the roller 6 before the roller 6 approximates to the drum 5 and the impressing of the developer is stopped after the roller 6 separates from the drum 5.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a developing device for an image forming apparatus such as an electrophotographic copying machine, facsimile, or printer that has a plurality of developing sections and forms two-color, multicolor, or full-color images. Regarding.

2. Description of the Related Art In general, image forming apparatuses such as color copying machines use the following methods to convert electrostatic latent images on a photoreceptor into visible images in different colors.
A method is used in which a plurality of developing sections are arranged and each developing section is selectively operated in sequence to obtain a color image. As a method for selectively operating the developing section, the developing section is configured to be retractable, and only a predetermined developing section having a developer carrier is pressed against the electrostatic latent image while carrying the electrostatic latent image. There are many methods used to separate the electrostatic latent image from the developer carrier when the electrostatic latent image is being carried.Other methods include not forming a layer of developer on the developer carrier when not developing. Alternatively, a method is used in which the height of the developing layer is lowered to prevent developer from adhering to the electrostatic latent image. Conventionally, the former method of moving the developing section involves operating a moving mechanism, Methods such as providing a slide guide and moving the developing section along the guide, or providing a support shaft and rotating the developing section around the support shaft are used.

Conventionally, when moving the developing section, a hopper for supplying developer into the developing section is also constructed integrally with the developing section and moved at the same time, or the hopper is provided and fixed in the main body of the image forming apparatus, and the developing section is moved at the same time. For example, a method of moving only the

Furthermore, in order to replenish toner in proportion to the amount of toner consumed in conventional development, a toner concentration sensor is installed in the developer stirring and mixing area in the developing device, and changes in the toner concentration of the developer are detected. Detected as a change in magnetic permeability,
A method is used in which the toner concentration of the developer in the developing device is kept constant (toner replenishment is controlled) based on this detected value.

In addition to this, in order to prevent developer from adhering to areas other than the image area, conventionally, when the electrostatic latent image is carried, a developing bias is applied that is slightly closer to the potential of the latent image than the potential of the area other than the latent image on the electrostatic latent image bearing body. By applying a voltage, an appropriate potential difference is created between the developer carrier and the latent image, and an appropriate amount of developer is electrically attached to the latent image area, and the developer is attached to areas other than the latent image. This prevents the so-called background fogging phenomenon.

Problems to be Solved by the Invention However, in the above-mentioned conventional configuration, forces are applied to the developing section due to the weight of the developing section itself and the rotation of the drive gear of the main body, and the developing section is subjected to a force that is too strong to be ignored from both of them. It was working. Both forces act in a direction that causes the developing section to escape from the photoconductor, or act in a direction that presses it against the photoconductor, and when the force acts in a direction that causes the development section to escape from the photoconductor, the force is A moving means that presses the developing section against the photoconductor with a large force is required, and conversely, when force acts in the direction of pressing the developing section against the photoconductor, a movement means that moves the developing section apart with a force greater than that force is required. A means was needed. In either case, an excessive force is required to move the developing section, resulting in a problem that the moving mechanism becomes complicated and large.

In addition, with the conventional method of moving the developing section and hopper as one unit, the moving mechanism becomes complicated due to the weight of the moving object.
There was a problem in that the driving force required for movement was large, and the overall size of the device was also increased. Furthermore, when the hopper is installed in the main body and only the developing section is moved, a gap is created because the joint between the hopper and the developing section shifts as the developing section moves. There is a problem in that the developer leaks out of the developing device and the inside of the image forming device is likely to be contaminated with the developer.

In addition, in order to achieve control of the toner concentration in the developer, it is necessary to constantly move the developer near the surface of the toner concentration sensor to accurately reflect the toner concentration in the developer. If the fluidity or stirrability of the developer changes due to changes in conditions, the developer on the sensor surface will not move and will stick to the sensor surface, making it impossible to accurately detect the toner concentration of the developer. There was a problem.

Furthermore, when developing while applying a developing bias, even if the developing bias is not applied just before the developing section is pressed, the developer is at a position extremely close to the body when carrying an electrostatic latent image. During carrying, the developer sometimes adhered to the non-image area of the body, causing background fog. In general, the above-mentioned background fog is outside the area of the image transferred to the paper, so it is not a big problem, but it is uneconomical as it consumes an unnecessary amount of developer. When using a two-component developer consisting of toner and carrier, if a developing bias is not applied, the potential difference between the developer carrier and the portions of the electrostatic latent image carrying body other than the electrostatic latent image will become large. , a carrier adhesion phenomenon occurs in which carrier charged with the opposite polarity to the toner adheres to that part, which not only smears the image but also damages the body while carrying an electrostatic latent image, and the carrier scatters inside the main body and damages the charged part. In addition, there was a possibility that a similar problem would occur when the developing section was separated.

The present invention is intended to solve the above-mentioned conventional problems,
To provide a developing device such as a color copying device, which can quickly move a developing section with a small and simple configuration, and can completely prevent leakage of replenishing developer even during movement. The purpose is to Another object of the present invention is to provide a developing device that can accurately control toner density, prevent background fogging and carrier adhesion, and produce clear and good images.

Means for Solving the Problems In order to achieve this object, the developing device of the present invention includes a developer carrier that is retractable and movable with respect to an electrostatic latent image carrier, and a developer carrier that is movable in a retractable manner with respect to an electrostatic latent image carrier, and a a moving means that is brought close to or in contact with the body when carrying a latent image, and is moved away from the body when carrying the electrostatic latent image when not being developed, and the moving means is brought into contact between the eccentric cam and the developing section by rotation of the eccentric cam. and is configured to create a state of contact and no contact.

Further, a predetermined developing bias is applied to the developer carrier before the developer carrier comes close to or comes into contact with the electrostatic latent image carrying body, and the application is stopped after the developer carrier is separated. It has a developing bias applying means for applying a developing bias.

The apparatus further includes a concentration detection means for detecting the toner concentration in the developing section, and a control means for controlling the amount of toner replenishment to the developing section based on the output from the concentration detecting means, and The image forming apparatus is configured such that vibration or impact is applied to at least the density detecting means during non-development.

A hopper for supplying developer to the developing section is disposed above the supply port of the developing section, and the supply port of the developing section is configured to move approximately vertically as the developing section moves. are doing.

Further, a rotatable spiral coil is provided inside the bendable tubular member, one end of the spiral coil is fixed to a hopper that stores the developer, and the other end is fixed to the developing section. A developer conveyance path is formed.

In addition, there is provided a developer carrier that is retractable and movable around a support shaft relative to the electrostatic latent image carrier, a drive gear for rotating the developer carrier, and a drive gear provided coaxially with the developer carrier. and a driven gear, wherein during development, the moving means engages the two gears to rotate the developer carrier, and during non-development, the moving means disengages the gears and stops rotation; Both gears and the support shaft are arranged so that the dependent gear moves in a direction substantially normal to a pitch circle of the drive gear as the developer carrier moves.

Further, the moment of force applied to the developing section due to the rotation of the driving gear about the supporting shaft is substantially equal to the moment of gravity applied to the developing section about the supporting shaft in opposite directions. Both gears and the support shaft are arranged so that

Operation With this configuration, the developing section can be quickly switched, and the developing bias is applied to the developer carrier earlier than when the developer carrier in the developing section approaches or contacts the electrostatic latent image carrying body.
Since application of the developer is stopped after the developer is separated, the problem of the developer adhering to the non-image area when the developer carrier is moved can be prevented. When a two-component developer is used in reversal development, carrier adhesion can be prevented, which is particularly effective.

Also, even if developer adheres to the surface of the toner density sensor,
Mechanical vibration or shock applied to the sensor removes the adhering developer from the sensor surface, removes the regular developer from the sensor surface, moves the regular developer across the sensor surface, and accurately aligns the toner in the developer. Concentration can be detected. Moreover, since the mechanical vibrations or shocks mentioned above are applied when the developing operation is not being performed, they do not adversely affect the developing operation.

Furthermore, the moving mechanism of the developing section has been simplified, and even if the developing section is moved, the developer supply port is always located below the supply port from the hopper, making it difficult for the developer to be supplied inside the developing section. The supply port of the hopper is larger than the supply port of the hopper, which prevents developer from spilling or scattering.

In addition, even if the developing section moves, the bendable tubular member deforms as it moves, so developer is always easily supplied from the hopper into the developing section through the tubular member, preventing spillage or scattering of developer material. Does not occur at all.

In addition, by configuring as described above, the driven gear moves from the normal direction of the pitch circle to the driving gear and meshes with the contact or proximity of the developing section, so the teeth mesh smoothly and drive is transmitted, resulting in meshing. The impact of time is small (possible).Also, when separating, it is impossible (gears become disengaged,
Drive transmission stops.

Furthermore, the moment of the weight applied to the developing section about the supporting shaft and the moment of the force applied to the developing section due to the rotation of the drive gear of the main body about the supporting shaft are balanced, so it is necessary to rotate the developing section about the supporting shaft. The movement of the developing section itself does not require a large force. Therefore, the moving mechanism can have a simple structure, and the developing section can be moved easily and quickly.

Embodiment FIG. 1 is a schematic cross-sectional view during development in the first embodiment of the present invention, FIG. 2 is an explanatory diagram of the acting force in the same embodiment, and FIG. FIG.

As shown in FIG. 1, the developing section 2 is held by a support shaft 1 and is movable around the support shaft 1. As shown in FIG. Due to the rotation of the eccentric cam 4 of the cam shaft 3, the developing section 2 is pressed against the photoreceptor 5 during development, and the developer 7 on the developing roller 6, which is a developer carrier, adheres to the electrostatic latent image on the photoreceptor 5. The image is then developed. Next, as shown in FIG. 3, during non-development, the camshaft 3 rotates again and the force of the return spring 8 causes the developing section 2 to be separated to a position where development is not possible.

In FIG. 2, during development, as the developing section 2 moves, the driving gear 11 provided on the main body and the driven gear 12 approach from a direction substantially normal to the Sochi circle and engage with each other, and the drive is transmitted.
During separation, the driven gear 12 moves in the normal direction, the meshing becomes separated, and the transmission of drive is stopped. At this time, since the driven gear 12 moves in the normal direction, the teeth mesh and disengage smoothly, making it possible to transmit and stop the drive.

As long as the direction of movement of the driven gear 12 is within the pressure angle of the gear with respect to the normal direction, there will be no problem in meshing. For example, for an involute gear with a pressure angle of 20 degrees, the tooth surface on the pitch circle is tilted 20 degrees from the normal line, so the gear will move within a range of plus or minus 20 degrees from the normal line. Any configuration is fine.

Then, when the developing section 2 is separated, a developing section (not shown) having a developer capable of developing with another color is pressed against the photosensitive pair 5 by a similar moving means to perform development. In this way,
A predetermined color image can be obtained quickly (by switching the developing section). In addition, in this embodiment, the drive gear 11 of the main body may be kept rotating at all times, or at least between the pressing and separating of the developing section 2. The rotation may be temporarily stopped at one time.

Note that 9 in the figure is a developer regulating member that regulates the flow rate of the developer 7, and 10 is a basket roller for squirting the developer 7.

According to this embodiment, in a developing device such as a color copying machine, with a simple configuration, it is possible to reliably move the developing section, transmit and stop the drive to the developing roller, reduce the impact during movement, It also prevents tooth skipping and damage to gears.

FIG. 4 is a schematic sectional view during development in the second embodiment of the present invention, FIG. 5 is an explanatory diagram of the acting force in the same embodiment, and FIG. 6 is a schematic sectional view during non-development in the same embodiment. It is a diagram.

As shown in FIG. 4, the developing section 15 is held by the support shaft 14 and is movable around the support shaft 14. As shown in FIG. During development, the rotation of the eccentric cam 17 of the camshaft 16 presses the developing section 15 against the photoreceptor 18, and the developer 20 on the developing roller 19, which is a developer carrier, forms an electrostatic latent image on the photoreceptor 18. It is attached and developed. During non-development, the camshaft 16 rotates again as shown in FIG. 6, and the force of the return spring 21 moves the developing section 15 away to a position where development is not possible.

Further, as shown in FIG. 5, during development, the drive gear 22 provided on the main body and the driven gear 23 that rotates the developing roller 19 mesh with each other, and the developing roller 19 rotates. At the meshing part, a force acts in the direction of the arrow that is inclined by the pressure angle of the gear with respect to the tangent to the pitch circle, and force A is applied to the developing section. For example, if the pressure angle is 20 degrees on a gear, the force A acts in a direction inclined at 20 degrees with respect to the tangent. Further, a force B in the vertical direction acts on the developing section 15 due to its own weight. and arrow A
The length Ll of the perpendicular line drawn from the center of the support shaft 14 to the extension line of
If the length of the perpendicular line drawn from the center of the support shaft 14 to the extension line of arrow B is L2, the magnitude of force A is a, and the magnitude of force B is b, then the force acting on the support shaft 14 is The moment is axL1 counterclockwise and bXL2 clockwise. Then, the position of the support shaft 14 is adjusted so that a×L1=bXL2.
Since the position, size, etc. of the quantity gear 22 are configured in relation to each other, no force is applied to rotate the developing section 15 about the support shaft 14. Therefore, the rotational torque of the camshaft 16 that moves the developing section 15 and the load on the return spring 21 are small (and the structure can be simplified).

In the embodiment shown in FIG. 2, the drive gear 22 and the driven gear 23 are in mesh with each other only during development, but they may be in mesh with each other all the time.

Further, after the developing section 15 is separated, a developing section (not shown) having a developer capable of developing with another color is pressed against the photoreceptor 18 by a similar moving means to perform development.

In this way, the developing section 15 can be quickly switched and a predetermined color image can be obtained. Note that 24 in China is a developer regulating member that regulates the flow rate of the developer 20;
5 is a basket roller for stirring the developer 20.

According to this embodiment, the developing section can be moved using a simple moving mechanism, and the developing section can be quickly switched to obtain a good image without color mixture.

FIG. 7 is a schematic sectional view during development in the third embodiment of the present invention, and FIG. 8 is a schematic sectional view during non-development in the same embodiment.

In FIG. 7, the developing section 26 is held by a support shaft 27,
It is movable around the support shaft 27. During development, the camshaft 28 rotates, and the eccentric cam 29 of the camshaft 28 moves the developing section 26 and presses it against the photoreceptor 30, causing the developer carrier 3
The developer 32 on the photoreceptor 30 adheres to the electrostatic latent image on the photoreceptor 30 and is developed. During non-development, the camshaft 28 rotates as shown in FIG. 8, and the force of the return spring 33 moves the developing section 26 away from the photoreceptor 30 to a position where development is not possible.

A hopper 34 that supplies developer 32 to the developing section 26 is fixed to the main body. The developer supply port 35 of the developing section 26 is
It is located on the upper surface of the developing section 26 and moves almost vertically as the developing section moves. The developer replenishment port 36 of the hopper 34 is located above the supply port 35, and the size of the replenishment port 36 is smaller than the size of the supply port 35. Therefore, even if the developing section 26 moves, the developer in the hopper 34 remains. 32 can be supplied, and the developer 32 will not leak outside. Also hopper 3
4 does not need to be moved, so the camshaft 2 required for movement
The rotational torque of 8 and the load of the return spring 33 can be reduced, the configuration can be simplified, and the space occupied by the developing device can be reduced.

Further, after the developing section 26 is separated from the photoreceptor 30, a developing section (not shown) having a developer capable of developing a different color is pressed against the photoreceptor 30 by a similar moving means to perform development. In this way, it is possible to quickly switch the developing section and obtain a predetermined color image.

In this embodiment, a support shaft 27 is provided and the developing section 26 is rotated around the support shaft 27, but as another method, a guide may be provided and the developing section 26 may be moved along the guide.

Further, in this embodiment, the developer supply port 35 is provided on the top surface of the development section 26, but a structure may also be adopted in which a supply port is provided on the front surface of the development section 26 to supply the developer 32 to the development section 26. good.

In the figure, 37 is a developer regulating member that regulates the flow rate of the developer 32, 38 is a basket roller that stirs the developer 32, and 39 is a developer replenishment roller that adjusts the amount of developer 32 supplied from the hopper 34. It is.

According to the developing device of this embodiment, it is possible to quickly (switch the developing section) with a simple configuration, prevent leakage of developer, and obtain a good image.

FIG. 9 is a schematic sectional view during development in the fourth embodiment of the present invention, and FIG. 10 is a schematic sectional view during non-development in the same embodiment.

In FIG. 9, the developing section 40 is held by a support shaft 41 and is movable around the support shaft 41. As shown in FIG. During development, the camshaft 4
2 rotates, and the eccentric cam 43 of the camshaft 42 causes the developing section 4 to rotate.
0 moves and is pressed against the photoreceptor 44, and the developer carrier 45
The upper developer 46 adheres to the electrostatic latent image on the photoreceptor 44, and the electrostatic latent image is developed. During non-development, the camshaft 42 rotates again as shown in FIG. 10, and the force of the return spring 47 moves the developer carrier 45 between the photoreceptor 44 and the development section 401 to a position where development is disabled. . Then, the developing section 4
When o is separated from the photoreceptor 44, a developing section (not shown) having a developer capable of developing with another color is pressed against the photoreceptor 44 by the same moving means as described above, so that the image is developed.
A predetermined color image can be obtained by quickly switching the developing section.

A hopper 48 that stores developer 46 is fixed to the main body. The hopper 48 and the developing section 40 are connected to each other by a bendable tubular member 49, and as a spiral coil 50 in the tubular member 49 rotates, the developer 46 passes through the tubular member 49 and leaves the hopper 48. It is supplied to the developing section 40.

Since the tubular member 49 is made of a bendable material, it is easily bent and deformed as the developing section 40 moves.
The developer 46 can be constantly supplied to the developer 46, and no leakage of the developer 46 occurs. Note that, since the hopper 48 does not move, the space occupied by the developing device is small. Since the length of the tubular member can be adjusted freely, the hopper 48 can be positioned away from the developing section 40, and the space occupied by the developing device is small. Since positional restrictions and size restrictions are relaxed, it is also possible to downsize the entire device.

In this embodiment, a support shaft 41 is provided and the developing section 40 is rotationally displaced around the support shaft 41, but another method is to provide a slide guide and move the developing section 40 along the guide. Good too.

Further, in this embodiment, a tubular member 49 is provided on the upper surface of the developing section 40.
The developer 46 was supplied from the front surface of the developing section 40 by connecting the tubular member 49 to the front surface of the developing section 40.
It may be configured to supply the following.

The material of the tubular member 49 is silicone rubber.

Urethane rubber etc. are suitable. Also polyethylene.

A bellows-like shape may be formed using a material such as polypropylene.

According to the developing device of this embodiment, it is possible to quickly (switch the developing section) with a simple configuration, and to completely prevent leakage of developer when supplying developer, thereby obtaining good images. be able to.

In addition, 51 in the figure is a developer regulating member that regulates the flow rate of the developer 46, and 52 is a basket roller for stirring the developer 46.

FIG. 11 is a schematic sectional view of the fifth embodiment of the present invention during development, and FIG. 12 is a schematic sectional view of the same embodiment during non-development.

In FIG. 11, a developing section 55 having a developer stirring member 53 and a toner concentration sensor 54 is held in the main body of the image forming apparatus by a support shaft 56, and the developing section 55 is retracted with respect to the photoreceptor 57 of the image forming apparatus. The developing section 55 is movable and is pressed against the photoreceptor 57 by an eccentric cam 58 . During development, the developer 5 is stirred by the rotation of the development stirring member 53.
9 are stirred, mixed, charged, and supplied to the developing roller 60. The developer 59 supplied to the developing roller 60 is conveyed to the developing area by the rotation of the developing roller 60, toner adheres to the electrostatic latent image on the photoreceptor 57, and the image is developed. A toner concentration sensor 54 is installed in the stirring and mixing area of the developer 59.
The toner concentration of the developer 59 is detected, and the toner 62 is supplied from the toner hopper 61 to the developing section 55 in order to keep the toner concentration constant.

FIG. 13 shows the relationship between the toner concentration in the developer 59 and the value detected by the toner concentration sensor 54. As shown in the figure, when the toner concentration decreases and the detection value of the toner concentration sensor 54 exceeds the reference value, it increases. Then, the output value of the toner concentration sensor 54 at a specified toner concentration is set as a reference value, and when the toner 62 is consumed and the toner concentration decreases, the output value of the toner concentration sensor 54 is adjusted based on that information. The toner 62 is supplied from the toner hopper 61 to the developing section 55, and the toner concentration of the developer 59 is kept constant.

When the development is completed, the rotation of the shaft 64 of the eccentric cam 58 and the return spring 65 cause the development section 55 to swing around the support shaft 56, causing the toner concentration sensor 54 to vibrate. Therefore, even if the developer 59 is attached to the surface of the toner concentration sensor 54, it is removed from the surface of the toner concentration sensor 54 by vibration. During development, the eccentric cam 58 stops at its original position and becomes ready for development, making it possible to accurately detect toner density.

Although the above embodiment has a configuration in which vibration is applied to the entire developing section 55 including the toner concentration sensor 54, it is of course possible to adopt a configuration in which vibration or impact is applied only to the toner concentration sensor 54.

Note that 66 in the figure is a developer member that regulates the flow rate of the developer 59.

According to the development position of this embodiment, even if developer adheres to the sensor surface, it can be removed mechanically by vibration or impact, so the toner concentration can be detected accurately, and the toner concentration of the developer can always be accurately detected. can be controlled.

FIG. 14 is a schematic sectional view during development in the sixth embodiment of the present invention, and FIG. 15 is a schematic sectional view during non-development in the same embodiment.

As shown in FIG. 14, a developing section 69 having a developer carrier 68 is held by a support shaft 67, and the developing section 69 is movable around the support shaft 67. Eccentric cam 7 of camshaft 70
1, the developing section 69 is pressed against the electrostatic latent image bearing member 72 during development, and the developer 73 on the developer carrier 68 is
is attached to the electrostatic latent image on the electrostatic latent image carrying member 72, and the electrostatic latent image is developed. During non-development, as shown in FIG. 15, the camshaft 70 rotates again, and the force of the return spring 74 causes the developing section 69 to be separated from the electrostatic latent image carrying member 72 and moved to a position where development is not possible. Since a developing bias applying means 75 (which performs a predetermined development on the developer carrier 68) is applied before the developing section 69 is pressed, background fogging and carrier adhesion do not occur, and the developing section 69, since the application of the developing bias is stopped after the separation, background fogging and carrier adhesion similar to those described above can be prevented. Furthermore, when the developing section 69 is separated from the electrostatic latent image carrying member 72, it has a developer 73 that can be developed in a different color.

Since a developing section (not shown) presses the electrostatic latent image against the member 72 and develops it, a predetermined color image can be obtained by quickly switching the developing section 69.

In the embodiment described above, the developing section 69 is held by the support shaft 67 and can be rotated around the support shaft 67, but a guide is provided and the developing section 69 is configured to move along the guide. Good too.

Note that 76 in the figure is a developer regulating member that regulates the flow rate of the developer 73, and 77 is a basket roller for stirring the developer 73.

According to the developing device of this embodiment, in a developing device such as a color copying machine, it is possible to smoothly and reliably switch the developing section, prevent background fogging and carrier adhesion, and always obtain clear and good images. Can be done.

Effects of the Invention As is clear from the above description, according to the developing device of the present invention, it is possible to move the developing section with a simple moving mechanism, and it is possible to quickly (switch the developing section) to produce a good image without color mixing. You can get a good image.

Moreover, it can prevent background fogging and carrier adhesion.
You can always get clear and good images. Furthermore, even if developer adheres to the sensor surface, it can be removed by mechanical vibration or impact, so toner concentration can be accurately detected and the toner concentration of the developer can always be correctly controlled.

Furthermore, leakage of the developer can be completely prevented when the developer is supplied, and good images can be obtained.

In addition, with a simple configuration, it is possible to reliably move the developing section, transmit and stop the developing roller, reduce impact during movement, and prevent tooth skipping and damage to the gear.

[Brief explanation of the drawing]

Figures 1, 4, 7, 9, 11, and 14
The figures are schematic cross-sectional views during development in the developing devices of the first to sixth embodiments of the present invention, FIG. 3, FIG. 5, and FIG.
Figures 10 and 12. and FIG. 15 are schematic cross-sectional views of the developing devices of the first to sixth embodiments of the present invention during non-development, respectively, and FIGS. 2 and 6 are the operations in the first and second embodiments, respectively. FIG. 13, an explanatory diagram of the force, is a diagram showing the relationship between the toner concentration in the developer and the detected value of the toner concentration sensor in the fifth embodiment. 1... Support shaft, 2... Development section, 3...
...Camshaft, 4...Eccentric cam, 5...
・Photoreceptor 1.6...Developing roller, 7...
...Developer. Figure 11 Figure 13 Figure 1-7-, J way (olo)

Claims (7)

[Claims] (1) A developer carrier that is retractable relative to the electrostatic latent image carrier, and the developer carrier is brought close to or in contact with the electrostatic latent image carrier during development, and supports the electrostatic latent image during non-development. 1. A developing device comprising a moving means for separating the developing unit from the developing unit, the moving unit creating a contact state and a non-contact state between the eccentric cam and the developing section by rotation of the eccentric cam. (2) a developer carrying pair that is retractable relative to the electrostatic latent image carrier; the developer carrying body is brought close to or in contact with the electrostatic latent image carrier during development, and is moved away from the electrostatic latent image carrier during non-development; a moving means for separating, and applying a predetermined developing bias to the developer carrier before the developer carrier approaches or contacts the electrostatic latent image carrier, and after the developer carrier is separated; A developing device comprising: a developing bias applying means for stopping application of a developing bias. (3) A developer carrier that is retractable relative to the electrostatic latent image carrier, and the developer carrier is brought close to or in contact with the electrostatic latent image carrier during development, and is moved away from the electrostatic latent image carrier during non-development. A moving means for separating the toner, a density detecting means for detecting the toner concentration in the developing section, and a control means for controlling the amount of toner supplied to the developing section based on an output from the density detecting means, and the moving means operates. A developing device characterized in that vibration or impact is applied to at least the density detecting means during non-developing. (4) A developer carrier that is retractable relative to the electrostatic latent image carrier, and the developer carrier is brought close to or in contact with the electrostatic latent image carrier during development, and is moved away from the electrostatic latent image carrier during non-development. A hopper for supplying the developer to the developing section is disposed above the supply port of the developing section, and as the developing section moves, the supply port of the developing section is moved in a substantially vertical direction. A developing device characterized in that it is configured to move. (5) A developer carrier that is retractable relative to the electrostatic latent image carrier, and the developer carrier is brought close to or in contact with the electrostatic latent image carrier during development, and supports the electrostatic latent image during non-development. A rotatable spiral coil is provided inside the bendable tubular member, one end of the spiral coil is fixed to a hopper that stores the developer, and the other end is fixed to a hopper that stores the developer. A developing device characterized in that a developer transport path is formed by being fixed to a developing section. (6) A developer carrier that is retractable about a support shaft relative to the electrostatic latent image carrier, and the developer carrier is brought close to or in contact with the electrostatic latent image carrier during development, and the developer carrier is brought into close proximity to or in contact with the electrostatic latent image carrier during non-development. The moving means is provided with a moving means for separating it from the electrostatic latent image carrier, a driving gear for rotating the developer carrying member, and a driven gear provided coaxially with the developer carrying member, and during development, the moving means As the developer carrier moves, the subordinate gear rotates the developer carrier by meshing both gears, and when not developing, the moving means disengages the gears and stops the rotation. A developing device characterized in that both gears and the support shaft are arranged so that the gears and the support shaft move in a direction substantially normal to a pitch circle of the drive gear. (7) A developer carrier capable of retracting and moving around a support shaft with respect to the electrostatic latent image carrier, which is brought close to or in contact with the electrostatic latent image carrier during development, and is brought into contact with the electrostatic latent image carrier during non-development. a driving gear for rotating the developer carrier, and a driven gear provided coaxially with the developer carrier; the moving unit meshes both gears during development. The center of the spindle is the center of the force applied to the developing section by the rotation of the drive gear, so that the developer carrier is rotated by the rotation of the driving gear, and when not developing, the moving means disengages the gears and stops the rotation. The developing device is characterized in that both the gears and the supporting shaft are arranged so that a moment of gravity applied to the developing section that stops the supporting shaft is substantially equal in magnitude in an opposite direction.