JP2975818B2 - Electrostatic image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic image forming apparatus, and more particularly to a clamshell type electrostatic image forming apparatus capable of improving image quality.

[0002]

2. Description of the Related Art A clamshell-type electrostatic image forming apparatus is an electrostatic image forming apparatus in which an outer casing of the apparatus is opened and closed like a clamshell, for example, as shown in FIGS. As shown in the drawing, the developing unit 1 is lifted together with the photosensitive drum 15 together with the upper shell half 28 when the upper half shell 28 of the outer casing 30 is swung around the fulcrum 16 to open the crumb. As shown in FIGS. 6 and 7, for example, when the upper half shell 28 of the outer casing 30 is swung around the fulcrum 16 to open the crumb, the developing unit 1 is moved to the lower shell. There is a method that is left on the half 29 side.

When the developing unit 1 is attached to the photosensitive drum 15 and opened upward, the developing unit 1 is guided by the slide rail 17 supported by the upper shell half 28 so as to be able to advance and retreat toward the photosensitive drum 15. The developing device 1 is supported by the shell half 28 and is pressed against the photosensitive drum 15 by the spring 11 so as to be in contact with the photosensitive drum 15 so that the developing device 1 is positioned at a fixed position with respect to the photosensitive drum 15. doing.

When the developing device 1 is left below when the shell is opened, the developing device 1 is pivotally connected to the lower shell half 29 when the shell is opened, and is positioned using a pin. The developing device 1 is mounted on the means 2 so as to be able to advance and retreat toward the photosensitive drum 15, so that the developing device 1 is not restricted by the apparatus main body.

Further, in this case, it is necessary to fix the developing device 1 to a predetermined position with respect to the photosensitive drum 15 when the shell is closed, so that the developing device 1 is pressed against the photosensitive drum 15 by the spring 11. The relative position between the developing device 1 and the photosensitive drum 15 in the radial direction of the photosensitive drum 15 is determined, and the developing device 1 is pressed against the positioning means 2 and the seat 31 by the spring 9 provided on the upper shell half 28. Thus, the relative position between the developing device 1 and the photosensitive drum 15 in the circumferential direction of the photosensitive drum 15 is determined.

In these systems, when the developing device 1 is opened upward on the photosensitive drum 15 side, the attaching / detaching direction of the developing device 1 is limited to the guiding direction of the guide rail 17, whereas the developing device 1 Is left on the lower side, the degree of freedom in the mounting / removing direction of the developing unit 1 is increased, so that the developing unit 1 remains on the lower side when the clam shell is opened so that the mounting / dismounting of the developing unit 1 is facilitated. A configuration is often adopted.

[0007]

In the developing device 1, a non-magnetic developer is used to transport the developer from a developer tank containing the developer to a developing area of the photosensitive drum 15. Is a developer roller, and when a magnetic developer is used, a roller-shaped developer conveying means 35 called a mag roller is provided. If necessary, stirring is performed to stir the developer in the developer tank. A paddle is provided.

In order to drive the developer conveying means 35 and the stirring paddle provided as necessary at the time of image formation, a driving force input gear is provided at the shaft end of the developer conveying means and the stirring paddle. A driving force output gear meshing with the driving force input gear is provided on the apparatus main body side.

For example, in the electrostatic image forming apparatus shown in FIG. 7, a sheet is fed from the right side to the left side in the figure, and the photosensitive drum 15 moves in a clockwise direction in which the lower peripheral portion moves in the same direction as the sheet conveying direction. Rotating. Further, a developer conveying means 35 disposed opposite to the developing area on the right side of the photosensitive drum 15
Is rotated in the counterclockwise direction opposite to the photosensitive drum 15.

Here, for example, a driving force input gear is fixed to the shaft end of the developer conveying means 35, and a driving force output gear meshing with the driving force input gear is connected to the driving force input gear from the side opposite to the photosensitive drum 15. If it is engaged, the driving force output gear is rotated clockwise in the opposite direction to the developer conveying means 35, and the driving force output gear is moved from the driving force input gear to the developing device 1.
Is exerted to lift the upper side. This force changes the relative position between the developing device 1 and the photosensitive drum 15 in the circumferential direction of the optical drum 15 against the pressure of the spring 9, and may cause deterioration in image quality due to jitter and skew.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. Jitter, skew, and the like caused by the movement of the developing device are restricted by restricting the movement of the developing device due to the driving force for driving the developing device. It is an object of the present invention to provide an electrostatic image forming apparatus capable of preventing occurrence of an image and improving image quality.

[0012]

SUMMARY OF THE INVENTION According to the present invention, there is provided a clamshell type electrostatic image apparatus in which a developing unit is left below when a clamshell is opened.
Positioning means for receiving the developing device at at least two places from the direction opposite to the driving force acting direction of the driving force input gear provided in the apparatus main body for driving the developing device when the clamshell is closed; and the driving force of the driving force input gear A spring for pressing the developing device against the positioning means from the same direction as the operation direction.

[0013]

In the present invention, when the image forming process is being executed during the clamshell closing, the developing device is pressed by the positioning means by the force acting on the developing device from the driving force input gear, whereby The relative position of the photosensitive drum with respect to the photosensitive drum in the circumferential direction is maintained at a fixed position. Further, in the present invention, when the image forming process is not being executed during the clamshell closing, the developing device is pressed by the positioning means by the pressure of the spring, and thereby, the photosensitive member in the circumferential direction of the photosensitive drum is The relative position with respect to the drum is kept at a fixed position.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show one embodiment of the present invention,
FIG. 1 is a perspective view of a main part of the embodiment when the clamshell is open, FIG. 2 is a schematic view of the embodiment when the clamshell is open, and FIG. 3 is a view of the embodiment when the clamshell is closed. It is a schematic diagram.

As shown in FIG. 2 and FIG.
It has an outer casing 30 composed of upper and lower shell halves 28 and 29, and the upper shell half 28 swings about the fulcrum 16 and is opened and closed.

As shown in FIG. 1, the lower shell half 2
9, a sheet is supplied from a paper feeding unit (not shown) to the photosensitive drum 1.
5, a paper guide 32 is provided to guide the lower transfer area, and both side edges of the paper guide 32 are turned up to displace the developing device 1 in a certain range in the vertical direction and the paper transport direction. A support wall 33 for supporting is formed.

In the developing device 1, guide pins 18, 19, 20, 21 projecting from both ends of the developer tank are formed on the support wall 33 corresponding to the guide pins 18, 19, 20, 21 respectively. Each U-shaped groove 22, 23, 24
25 is mounted on the apparatus main body by fitting it from above.

On the paper guide 32, springs 7, 8, 9, and 10 are arranged at four corners of the developing unit 1 mounted on the apparatus main body in a plane projection, as shown in FIGS. 2 and 3. The developing device 1 mounted on the apparatus main body is supported by these springs 7, 8, 9, 10.

An optical system (OP section) 6 shown in FIG. 1 is incorporated in the upper shell half 28, and the photosensitive drum 15 is rotatably supported on the bottom side of the optical system 6 via a pair of brackets 34. Is done. When the shell half is closed as shown in FIG. 3, the photosensitive drum 15 pushes the developing unit 1 toward the paper supply side, and the spring 11 provided on the lower shell half 29 is elastically deformed, thereby restoring the elasticity of the spring 11. The developing device 1 is pressed against the photosensitive drum 15 by force, so that the relative position of the developing device 1 to the photosensitive drum 15 in the radial direction of the photosensitive drum 1 is kept constant.

A pair of pins 2 and 3 for receiving the tapered portions 26 and 27 formed on the photosensitive drum 15 side of the developing device 1 from above when the clamshell is closed are fixed to the surfaces of the bracket 34 facing each other. Further, bosses 4 and 5 received on the bottom surface of the optical system 6 when the clamshell is closed are provided on the upper side of the developer tank of the developing device 1 on the side of the paper feeding section.
Is protruded. The pins 2 and 3 and the bottom surface of the optical system 6 constitute positioning means for regulating the relative position of the developing device 1 to the photosensitive drum 15 in the circumferential direction of the photosensitive drum 15.

As shown in FIG. 3, when the clam shell is closed, the positioning pins 2 and 3 are connected to the tapered portion 26 of the developing device.
27, and the bottom surface of the optical system 6 comes into contact with the bosses 4.5 of the developing device 1 to push the developing device down to its proper position, whereby the springs 7, 8, 9, 10 are elastically deformed. By pressing the developing device 1 against the positioning means with the elastic restoring force of the springs 7, 8, 9, and 10, the relative position of the developing device 1 with respect to the photosensitive drum 15 in the circumferential direction of the photosensitive drum 15 becomes constant. Will be retained.

As shown in FIG. 1, the developing device 1 includes a photosensitive drum 1 at an end of the developer tank on the photosensitive drum 15 side.
5 is provided with a roller-shaped developer conveying means 36 parallel to
The drive input gear 12 is fixed to the shaft end of the developer conveying means 35.

On the other hand, as shown in FIGS. 2 and 3, the photosensitive drum 15, positioning means and springs 7, 8, 9, 10, 11 are positioned at predetermined positions on the apparatus body side. A drive output gear 13 is provided so as to mesh with the drive input gear 12.

In FIG. 3, the sheet is conveyed from right to left, and the photosensitive drum 15 is rotated clockwise so that the peripheral surface moves in the same direction as the sheet in the lower transfer area.
Further, the developer conveying means 36 of the developing device 1 and the drive input gear 1
Numeral 2 rotates counterclockwise so that the peripheral surface moves in the same direction as the peripheral surface of the photosensitive drum 1 in the developing area on the right side of the photosensitive drum 15.

Therefore, the direction of the reaction force 14 due to the transmission torque generated at the meshing position between the drive output gear 13 and the drive input gear 12 acts in the direction in which the developing device 1 moves between the positioning means, and the photosensitive drum 15 Since the relative position of the developing device 1 in the circumferential direction with respect to the photosensitive drum 15 does not change, jitter and skew due to the change in the position of the developing device 1 do not occur, and the image quality can be improved.

[0026]

As described above, according to the present invention, the developing device is driven at least from the direction opposite to the driving force acting direction of the driving force output gear provided in the apparatus main body for driving the developing device when the clam shell is closed. Positioning means for receiving at two locations and a spring for pressing the developing device against the positioning means from the same direction as the driving force acting direction of the driving force output gear are provided. As a result, the relative position of the developing device to the photosensitive drum in the circumferential direction of the photosensitive drum due to the moving force of the driving force output gear is reliably prevented from fluctuating. Since the occurrence of image defects is reliably prevented, image quality can be improved.

[Brief description of the drawings]

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

FIG. 2 is a schematic diagram when a clamshell is opened according to an embodiment of the present invention.

FIG. 3 is a schematic diagram when the clamshell of the present invention is closed.

FIG. 4 is a schematic view of a conventional example when a clamshell is opened.

FIG. 5 is a schematic view of a conventional example when a clamshell is closed.

FIG. 6 is a schematic view of another conventional example when a clamshell is opened.

FIG. 7 is a schematic view of another conventional example when the clamshell is closed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Developing device 2, 3 pin 4, 5 Boss 6 Optical system 7, 8, 9, 10, 11 Spring 12 Driving force input gear 13 Driving force output gear

Claims (1)

(57) [Claims] 1. A driving force output gear provided in a main body of a device for driving a developing device when a clamshell is closed in a clamshell-type electrostatic image device in which a developing device is left below when a clamshell is opened. Positioning means for receiving the developing device at at least two places from the direction opposite to the force acting direction; and a spring for pressing the developing device against the positioning means from the same direction as the driving force acting direction of the driving force output gear. Electrostatic image forming apparatus.