JPS61282876A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent a device from being fouled and its picture quality from deteriorating by running an image carrier by a proper extent in the opposite direction from that in image formation when a cleaning means is attached to or detached from an image forming device. CONSTITUTION:A cylindrical photosensitive body 3 is fitted rotatably on a shaft 3a fixed at a proper position of the upper half part 1a of a copying machine body. The casing 11 of the cartridge including a developing device 5, a cleaning device 4, and a primary electrostatic charger is provided with plural pins 11c-11f and holes 1c-1f corresponding to them are bored, so the respective pins are inserted into the corresponding holes at the final stage of cartridge insertion to set the cartridge at a fixed position. When the cartridge is detached, a microswitch 22 is turned on by an actuator part 11h for a specific time and the photosensitive body is reversed slightly by a motor 24 through a controller 23.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Object of the Invention (Field of Industrial Application) The present invention relates to an image forming apparatus using an electrostatic transfer process, such as an electrophotographic copying machine and a printer thereof.

(Prior art and issues to be solved) After forming a transferable toner image on a continuously running image carrier, this is transferred to a sheet-like transfer material mainly made of paper, and then the toner image remains on the image carrier. In a well-known image forming apparatus that repeats the process of removing residual toner, a cylindrical image carrier is used as the continuously running image carrier, and a cleaning blade made of an elastic material such as rubber is used as the residual toner removing means. Those using this method have been widely used in practice.

FIG. 6 is an example showing only the vicinity of the cleaning device of such an image forming apparatus, in which the cleaning device C is arranged parallel to the central axis of the cylindrical image carrier.

One edge of an elastic cleaning blade B is attached to the cleaning device, and the other free edge is pressed against the surface of the image carrier.

The image carrier rotates in the direction of arrow A, and a transfer site (not shown) is arranged upstream of the cleaning device, where transfer is performed onto a transfer material (not shown). It is assumed that the residual toner remaining on the surface of the image carrier without contributing to the image carrier is conveyed to the position of the cleaning blade B as the image carrier rotates, and is scraped off by the blade.

In such a leaning device, the toner that reaches the edge of the blade B is not scraped off one after another each time, but instead accumulates a small amount on the edge portion as shown by the symbol T and then falls. It has been confirmed that

In addition, the cleaning device may be taken out for maintenance, repair, etc. In such cases, when installing or removing the cleaning device, be sure to take precautions to prevent parts of the cleaning device from colliding with the image carrier and damaging the surface photoconductive layer. , it is common to use a guide rail to retreat from a predetermined position to a position C1 in the figure.

For this reason, when the blade separates from the image carrier,
The toner accumulated on the surface of the image carrier remains as it is, and when the cleaning device is attached next and the blade comes into contact with the surface of the image carrier, the edge of the blade is removed from the toner pool T.
In some cases, the image bearing member comes into contact with the image carrier at the inside or upstream side thereof.

If image forming work is started in such a state, toner downstream from the edge may be peeled off from the image bearing member at an unfavorable time, scattering into the image forming apparatus, contaminating various parts, or falling onto the transfer material. This causes inconveniences such as deterioration of image quality.

In recent years, developing devices,
Increasingly, it has become common to prepare multiple cartridges each having a cleaning device integrally formed therein, each developing device storing a different color toner, and replacing the cartridges as needed to obtain a multicolor image. However, in such cases, as mentioned above, when replacing the cartridge and therefore the cleaning device, some of the toner of the previously used color may be mixed with toner of a different color, resulting in an inaccurate color image. There is a risk that you will not be able to obtain it.

The present invention has been made in order to cope with the current situation, and when the cleaning device is attached or detached, the edges of the cleaning grade are removed upstream of the toner left on the surface of the image carrier during the previous image forming operation. It is an object of the present invention to provide an image forming apparatus that can prevent the image forming apparatus from being soiled and deteriorating the image quality as described above by making contact with the image forming apparatus.

(2) Structure of the invention (technical means for solving the problem and its operation) In order to achieve the above object, the present invention includes a moving image carrier and a cleaning device having a cleaning blade that comes into contact with the image carrier. In the image forming apparatus, when the cleaning device is attached to and detached from the image forming apparatus, the image carrier is configured to travel a certain amount in the opposite direction to that during image forming operation.

With this configuration, when the cleaning device is installed next time, the edge of the cleaning blade can definitely come into contact with the toner pool formed during the previous operation on the surface of the image carrier on the downstream side. The toner accumulation will not cause staining of the device or deterioration of image quality.

(Description of Embodiments) Hereinafter, an embodiment in which the present invention is applied to a copying machine employing a cartridge system will be described.

FIG. 1 is a side view schematically showing the configuration of such a copying machine. Inside the copying machine 1, an image carrier (photoreceptor) 3 that rotates in the direction of the arrow in the figure is arranged, and its surroundings are includes a primary charger 4, a lens array that receives reflected light from a light beam projected onto a document (not shown) on the top surface of the copying machine and forms an image on the surface of the photoreceptor to form an electrostatic latent image; Disposed are members necessary for image formation, such as a developing device 5 that supplies toner to the image to make it visible, a transfer charger 8 that performs transfer, and a cleaning device 7 that removes residual toner on the photoreceptor.

Further, in the illustrated embodiment, the charger 4, the developer 5, and the cleaning device 7 are attached to the casing 11, and these members together form a cartridge. When the toner runs out, when a different color image is to be formed, etc., the cartridge is installed and removed as a unit by displacement along guides 15 and 16 in a direction perpendicular to the plane of the paper (details on these will be described later). do).

The developing device 5 is pivotally connected to the casing 11 by a pin 5a, and is rotated clockwise in the drawing by a lever spring 13, and the cleaning device 7 has a protrusion formed thereon that engages with an opening formed in the casing. They are rotatably attached to each other and are provided with a clockwise rotational tendency as shown in the figure by a spring 14.

In the illustrated operating position, the developing device 5 is held in place by the guide 15 and the cleaning device 7 by the guide 16 against the action of the springs 13, 14, respectively.

Further, the copying machine main body 1 that supports the cartridge, photoreceptor, etc. has an upper half la and a lower half 1 with the chain line S as the boundary.
b, and the upper half 1a has a pin 19.
It is configured so that it can be rotated to open and close with respect to the lower half 1b around the center (see Fig. 2).

As can be seen from FIG. 1, the lower half 1b of the illustrated copying machine
includes a paper feed roller 6, a registration roller 9, a transfer charger 8, a transport path 17, a fixing device 10. A paper discharge tray 12 and the like are arranged.

Image forming operations performed by this copying machine are not particularly different from those performed by well-known copying machines of this type, so a description thereof will be omitted.

The aforementioned cartridge includes a mechanism to prevent damage to the photoconductor when loading and unloading it into the copying machine body, a mechanism to prevent toner dissipation from the cleaner when loading and unloading it and storage, a mechanism for positioning the cartridge with respect to the copying machine body, and a photoconductor and developer. A drive mechanism for the sleeve is provided and will be described below.

First, a mechanism for preventing damage to the photoconductor will be explained.

FIG. 3 is a side sectional view showing the structure of the cartridge taken out from the main body of the copying machine, in which a primary charger 4, a developing device 5, and an IJ-ning device 7 extending perpendicularly to the plane of the paper are arranged. be. The charger 4 is fixed at a predetermined position in the casing 11 of the cartridge, and the developer 5 is arranged so as to be able to swing freely by a pin 5a attached to the side wall of the casing, and furthermore, the developing device 5 is always rotated clockwise by a spring 13. It is given. Furthermore, the developing device is provided with a protrusion 5b, which in the illustrated natural state is engaged with a protrusion 11a formed on the casing side to maintain the developing device 5 at the "maximum movement position" in the clockwise direction. .

The cleaning device 7 is rotatably supported by a pin 7b fixed to the side wall of the casing, and a protrusion 7a provided at the top of the cleaning device 7 is fitted into an opening 11b formed in the casing. This action maintains the cleaning device 7 in its maximum clockwise rotation position.

That is, when the cartridge shown in FIG. 3 is taken out, the developing device 5 is held at a position close to the photoreceptor, and the cleaning device 7 is held at a position at a distance from the photoreceptor.

As described above, guides 15 and 16 for loading and unloading the cartridge are formed in the upper half 1a of the main body of the copying machine.

Figures 4 to 4C show the configuration of these guides 15 and 16, and Figure 4A is a view from below when the developing device 5 and cleaning device 7 are installed in the cartridge. shall be installed from the direction indicated by the arrow.

FIG. 4B is a perspective view of the main part of the guide 15 seen from the side where the developing device is installed, with arrow A pointing toward the operator's side and the car 1.
- The IJ joint is installed in the direction of the arrow.

When the cartridge in the normal position is advanced in the direction of the arrow by the positioning means described later, the protrusion 5C provided on the developing device 5 comes into contact with the slope 15a of the guide 15, and is guided by the protrusion 5C1, so that the developing device 5 , in the counterclockwise direction in FIG. 3, thereby also displacing the developing sleeve 5d inside the device in a direction away from the photoreceptor.Then, when the protrusion 5C reaches the parallel surface 15b of the guide, the developing device 5 and its The inner sleeve 5d is maintained at a position away from the photoreceptor and enters the main body of the copying machine.

Immediately before the developing device 5 and the photoreceptor 3 reach a predetermined opposing position, the protrusion 5C rotates along the slope 15c of the guide 15, and the sleeve 5d approaches the photoreceptor.

As is well known, spacers are formed at both ends of the developing sleeve 5d in order to maintain a predetermined distance between the developing sleeve 5d and the surface of the photoreceptor at a fixed position.

Therefore, when the protrusion 5C1 and therefore the developing device 5 approach the photoreceptor to some extent along the slope 15C, the spacer comes into contact with the photoreceptor, and thereafter, due to the action of the spring 13, the developing device 5,
The sleeve 5d will be maintained in normal position.

When removing the cartridge, if the cartridge is pulled out in the opposite direction to arrow A, the protrusion 5C will be displaced along the slope 15C, and the developing sleeve 5d will be separated from the photoreceptor by a predetermined distance, and the cartridge will be pulled out in this state. It is easy to understand what will happen.

As described above, the cleaning device 7 is at the maximum position of clockwise rotation in FIG. 3, and the cleaning blade and the like disposed thereon are at a position separated from the surface of the photoreceptor.

When the cleaning device is attached to the copying machine body together with the cartridge in this way, that is, when the car 1-IJ screw is moved in the eight directions of the arrows in FIGS. Plane part 1
6a (the surface on the side where the photoreceptor is present), and rotates the entire cleaning device in the same direction by rotating counterclockwise against the action of the spring 14 along the slope 16b at the pre-fixed position. The protruding portion 7C further reaches the flat portion 16c, and the position of the cleaning device 7 relative to the surface of the photoreceptor is determined. It is assumed that the cleaning blade operates normally in this position.

When the cartridge is pulled out, the protrusion 7C becomes the slope 16b.
The photoreceptor is then removed from the photoreceptor, and is then guided by the flat portion 16a and pulled out as it is.

The internal structure of the cleaning device will be further explained with reference to FIG. 3. Inside the casing of the cleaning device is a pair of scoop sheet support arms 18 (only one of which is shown in the figure) fixed to the aforementioned fixing pin 7b. ) and the scooping sheet 20 and cleaning blade 21 attached to it are profitable.

When the cartridge is taken out to the outside as shown in FIG. 3, the scooping sheet 20 is maintained in a fixed state.
The free edge of the cleaning blade 21 is arranged in such a manner that the free end edge of the cleaning blade 21 overlaps the inner side of the cleaning blade 21.

As described above, when the casing of the cleaning device is rotated counterclockwise when a cartridge is installed, the cleaning blade also rotates in the same direction, and when the cleaning device is at a predetermined operating position, the blade 21 An opening is formed between the free edge of the scoop sheet and the free edge of the scoop sheet.

As shown in FIG. 3, the casing of the cleaning device 7 and the arm 18. When the scooping sheet 20 rotates relatively, the difference between the relative rotation radius 'FL1 of the arm 18 with respect to the casing and the rotation radius R2 of the inner wall surface of the casing is configured to be as close to the thickness of the scooping sheet 20 as possible. As a result, the outer surface of the scooping sheet and the inner wall surface of the casing rub against each other, thereby preventing the toner from escaping.

In addition, when the cleaning blade is displaced from the operating position to the non-operating position shown in the third figure, the position direction of the rake sheet and the free edge of the blade is adjusted so that the free edge of the blade rubs against the inner surface of the rake sheet 20. shall be determined.

With the above structure, both the developing device and the cleaning device are separated from the photoreceptor when the cartridge is installed or removed, so that the photoconductive layer is not damaged. Further, in the cleaning device, in its non-operating position, the cleaning blade and the scooping sheet are in an overlapping state, so that it is possible to prevent toner from dissipating.

Next, the cartridge positioning mechanism will be explained.

FIG. 5 is a partially cut-away plan view of a positioning mechanism for accurately seating the cartridge in a predetermined position when the cartridge is installed in the copying machine main body along the aforementioned guides 15 and 16.

A cylindrical photoreceptor 3 is rotatably attached to a shaft 3a fixed in a proper position in the upper half 1a of the main body of the copying machine.

A car 1-IJ screw, which is equipped with a developing device 5, a cleaning device 4, and a primary charger (not shown), is installed from the direction of the arrow along the guide configured as described above.

The cartridge casing 11 has a plurality of vias lie, lid, lie and llf as shown.
Since the corresponding holes 1c, ld, le, and 1f are provided in the upper half 1a of the copying machine main body, each pin is inserted into the corresponding hole in the final step of cartridge insertion, and the cartridge is inserted into the cartridge. will fall into place.

Furthermore, a hole 31 is formed at the free end of the shaft 3a, and a pin l1 provided in the casing 11 is inserted during mounting.
g is locked in this hole 31, and as a result, the photoreceptor 3, which is supported in a cantilevered manner when there is no cartridge, becomes supported on both sides and can stably rotate.

Next, the drive system will be explained.

A gear 3b is fixed to the end of the photoconductor 3 on the side opposite to the operator side, and this gear connects to the gear 25 attached to the shaft of the motor 24.
The gear 25 rotates in response to a print command and rotates the photoreceptor 3. One end of the sleeve 5d inside the developer 5 protrudes from the developer casing, and a gear 29 is disposed on this sleeve 5d. .

A gear 27 is attached to a drive shaft 26 protruding from the main body of the copying machine near the cartridge, and an arm 30 is rotatably disposed on the shaft.

As can be seen from FIG. 2, the arm 30 is given the ability to rotate clockwise in the drawing by a spring 33, and its movement is prevented by a stopper pin 32 provided on the main body side.

A gear 28 is disposed on the arm 30, and is adapted to engage and disengage from the aforementioned gear 29 on the sleeve side.

With this structure, when the cartridge is installed in the copying machine main body, the tips of the gears 29 and 28 may come into contact with each other when the developing device is rotated toward the photoreceptor. However, due to the pressing force of the developing device, the spring 3
3, the arm 30 and the gear 28 do not prevent the sleeve from reaching the predetermined position. Thereafter, the shaft 26 and gears 27 and 28 are operated in response to the copy command, and in combination with the action of the spring 33, the gears 28 and 29 are engaged and the sleeve 5d is rotated.

An actuator portion 11h is provided at a suitable position on the side plate of the cartridge casing 11 on the operator side, and this turns on a microswitch 22 disposed on the main body side for a short period of time when the cartridge is attached or removed.

As a result, the motor 24 is reversely rotated via the controller 23, and the photoreceptor is rotated slightly in reverse.

As a result, even if there is a toner pool on the surface of the photoconductor, when the cartridge is brought to the regular position, the toner pool will be upstream of the pressure contact edge of the cleaning blade, so that the edge will directly collide with the toner pool. Never happened.

Although the present invention has been described above with reference to a case where it is applied to a cartridge-type copying machine, it is easy to understand that the present invention is not limited to this and can also be applied to a paper-type image forming apparatus. Dew.

(3) Effects of the invention Since the present invention has the configuration and operation described above,
Even if a toner puddle is formed on the surface of the image carrier, the next time the cartridge is installed, the cleaning blade will come into contact with the area where there is no toner puddle, so the toner in the toner puddle will fall and stain various parts inside the image forming apparatus. The present invention does not cause any deterioration in image quality, and can effectively prevent color turbidity due to color mixing even when making multicolor copies.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of a copying machine in which the present invention is applied to a cartridge-type copying machine, and FIG. 2 is a side view showing the main body rotated open with the cartridge removed. Figure 3 is a side sectional view of the cartridge, Figure 4A is a bottom plan view of the main part showing the cartridge installed, Figures 4B and 4C are perspective views of the main part showing the guide, and Figure 5 is a positioning and FIG. 6 is an explanatory view showing the operation of the cleaning device. FIG. 1... Copying machine main body, 2... Lens array, 3...
Photoreceptor, 4... - Charger, 5... Developer, 7...
・Cleaning device, 15.16... Guide for curly ridge, 21... Cleaning frame, 22...
・Micro switch, 23... Controller% 24
...Drive motor, 25.27.28.29...Gear. Figure 4C

Claims (1)

[Scope of Claims] After a transferable toner image formed on the surface of a moving image carrier is transferred to a transfer material, residual toner remaining on the surface of the image carrier is removed by a cleaning means provided with an elastic cleaning blade. An image forming apparatus according to the present invention, further comprising a means for moving the image carrier by an appropriate amount in a direction opposite to that during image formation when the cleaning means is attached to and detached from the image forming apparatus.