JPS63137285A - Image forming device - Google Patents

Abstract

PURPOSE:To surely remove a toner to extend the life of a photosensitive body by increasing the pressing pressure of a blade to the photosensitive body when a toner image for quality check is scraped. CONSTITUTION:With respect to a device where the toner image for quality check can be formed on an area other than a prescribed area of the photosensitive body, a supporting plate 23 can be turned by a shaft 25 and is horizontally arranged, and a blade 22 is provided in the end part with a T-shaped member 24 between them and is approximated to a photosensitive drum 10. A weight 26 is provided in the other end, and an engaging projection 29 and a solenoid 28 on a housing 21 are connected by a wire 27. When the solenoid 28 is turned on, the plate 23 is turned against the weight 26 to separate the blade 22 from the drum 10. The side part of a pressing plate 31 is loosely fitted to the shaft 25 in an aperture 23a of the plate 23, and an engaging projection 34 in the side end, where a weight 32 is arranged, of the plate 31 and a solenoid 36 are connected by a wire 35. When the solenoid 36 is turned on, the plate 31 is turned upward and is separated from the plate 23, and it is set to such position that it is not brought into contact with the plate 23 when the solenoid 28 is turned on. Both solenoids are controlled to increase the blade pressure only at the time of scraping the toner image for quality check, thus reducing the degradation due to friction of the photosensitive body.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention develops an electrostatic latent image formed on a photoreceptor with toner, and then transfers the toner image onto a transfer paper or the like to obtain an image. The present invention relates to an image forming apparatus, and particularly relates to an image forming apparatus capable of scraping off residual toner on a photoreceptor with a blade after a predetermined electrophotographic process has been completed.

(Prior Art) An image forming apparatus, for example, an electrophotographic copying machine, forms a predetermined electrostatic latent image on a photoreceptor, develops the electrostatic latent image with toner, and then transfers the toner image onto a transfer paper. A copy image is obtained by transferring. The photoreceptor, on which the toner image has been transferred to the transfer paper, is subjected to a primary copying process after residual toner adhering to the surface of the photoreceptor is removed by a cleaning device.

The cleaning device 9 usually uses a blade made of an elastic material such as rubber, and scrapes off residual toner on the surface of the photoreceptor by bringing the tip of the blade into pressure contact with the surface of the photoreceptor.

Recently, in electrophotographic copying machines, it is possible to form a toner image for image quality inspection in an area other than the area on the photoreceptor where the copied image is to be formed, and to improve the quality of the copied image based on the formed toner image. It is being done.

For example, an original to be copied on the original platen is placed in a non-exposed area, and an original for one-image quality inspection is placed, and when the original on the original platen is exposed to the photoreceptor, this original is exposed Before printing, the original for image quality inspection is exposed to light on a photoreceptor to form an electrostatic latent image. An electrostatic latent image corresponding to the image of the document to be copied is formed behind the electrostatic latent image on the photoreceptor.

Then ζ.

For example, the density of a toner image obtained by toner development of an electrostatic latent image corresponding to a document for image quality inspection is measured.

The toner density control device is controlled so that the measured value becomes a predetermined target value, and a copy image having a predetermined toner density is obtained. Furthermore, the potential of an electrostatic latent image obtained by exposing a document for two-image quality inspection is measured to control the amount of charge, the amount of exposure, and the like.

The toner image formed on the photoreceptor is for image quality inspection.

It is removed by the cleaning device without being transferred to the transfer paper. A toner image for copying is formed behind the toner image for image quality inspection on the photoconductor, and the cleaning device cleans the toner image for copying after the toner image for copying is transferred to the transfer paper by the transfer device.

Toner remaining on the photoreceptor is also removed.

In this way, the 9 image quality test toner images are removed by the cleaning device without being transferred to the transfer paper. In a cleaning device using a blade, the contact pressure of the blade against the photoreceptor is usually set so that the toner remaining on the photoreceptor after being transferred to the transfer paper can be removed.

Therefore, high-density toner images for image quality inspection that are not transferred to transfer paper.

Such a blade cannot scrape off completely. In order to completely remove the toner image for image quality inspection, it is sufficient to increase the blade pressure, but if the blade pressure is increased,
The deterioration of the photoreceptor becomes severe and the life of the photoreceptor is significantly shortened. Also, strong force is required to drive the photoreceptor.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems, and its purpose is to reliably remove a toner image for image quality inspection, and to reduce the friction of the photoreceptor. An object of the present invention is to provide an image forming apparatus that can suppress deterioration as much as possible and extend the life of a photoreceptor.

(Means for Solving the Problems) The image forming apparatus of the present invention transfers a toner image formed in a predetermined area on a photoreceptor to a transfer paper.

An image forming apparatus capable of removing toner remaining on the photoreceptor by bringing a blade into contact with the photoreceptor, and forming a toner image for image quality inspection in an area other than a predetermined area on the photoreceptor, The toner image for image quality inspection is scraped off by increasing the contact pressure of the blade against the photoreceptor, thereby achieving the above object.

(Example) Examples of the present invention will be described below.

As shown in FIG. 1, the electrophotographic copying machine of the present invention has a photosensitive drum 10 approximately in the center of the machine body.

Above the photoreceptor drum 10 is a movement area for the optical system 11, and the optical system 11 reciprocates within this movement area. An original placing table 12 is disposed above the moving range of the optical system 11, and when the optical system 11 moves forward, the optical system 11 captures the image of the original for copying placed on the original placing table 12. The body drum 10 is exposed to light. On the back side of the upper plate of the machine body adjacent to the exposure start side of the original table 12.

An image quality inspection original 13 is attached facing downward.

When the optical system 11 exposes the original for copying placed on the original placing table 12, the optical system 11 first exposes the original for image quality inspection 13.
is exposed first.

The photoreceptor drum 10 is arranged to be rotatable in the direction shown by arrow A, and a charging device 14 is installed on the upstream side in the rotational direction of the photoreceptor drum at a position where the optical system 11 exposes the surface of the photoreceptor drum 10. It is arranged opposite to the drum 10. The charging device 14 uniformly charges the photosensitive drum 10. A developing device 15 is disposed downstream of the exposure position of the surface of the photoreceptor drum 10 by the optical system 11 in the direction of rotation of the photoreceptor drum. The electrostatic latent image formed on the surface is developed with toner.

A downstream side of the developing device 15 in the rotational direction of the photoreceptor drum,
Below the photoreceptor drum 10, a transfer device 16 and a separation device 17 are arranged in parallel in the rotational direction of the photoreceptor drum 10. The transfer device 16 transfers only the toner image corresponding to the original for copying on the photosensitive drum 10 developed by the developing device 15 onto a transfer paper, and the separation device 17 photosensitively transfers the transfer paper onto which the toner image has been transferred. It is separated from the body drum 10.

A cleaning device 20 is provided at a position facing the developing device 15 with the photosensitive drum 10 in between.

The cleaning device 20 removes toner attached to the photoreceptor drum 10 by the developing device 15.

The cleaning device 20, as shown in FIGS. 2 and 3, has a blade 22 disposed within a housing 21 having an opening 21a. Opening 2 of housing 21
1a is opened so as to face the drum 10,
The blade 22 is supported so as to come into contact with the surface of the drum 10 through the opening 21a.

The blade 22 has a flat plate shape made of an elastic material such as rubber, and is attached to the tip of a support plate 23 via a mounting member 24 so as to be parallel to the axis of the I:fA light drum 10. installed.

The support plate 23 is disposed substantially horizontally within the housing 21 so as to be rotatable around a support shaft 25, and a blade is attached to the end of the support plate 23 near the photoreceptor drum 10 via a mounting member 24 having a T-shaped cross section. The upper end of 22 is attached.

Then, by rotating the support plate 23 on the side where the blade 22 is disposed downward, one side edge of the lower end of the blade 22 on the photoreceptor drum 10 side can come into contact with the surface of the photoreceptor drum 10.

A weight 26 is attached to the side of the support plate 23 opposite to the side where the blade 22 is disposed, and the support plate 23 is
2 urges the support plate 23 so that it comes into pressure contact with the photoreceptor drum 1o at a predetermined pressure.

An engaging protrusion 29 is provided on the side of the support plate 23 where the weight 26 is provided. One end of a wire 27 is locked to the engagement protrusion 29, and the other end of the wire 27 is connected to the housing 2.
The lower end of a plunger 28a of a solenoid 28 disposed on the upper surface of the solenoid 1 is engaged with the lower end of a plunger 28a which is movable in the vertical direction. In the off state where the solenoid 28 is not energized,
The plunger 28a is pulled by the weight 26 and moves downward. When the plunger 28a is turned on, the plunger 28a is moved upward and rotates the support plate 23 against the biasing force of the weight 26, thereby moving the blade 22 onto the photoreceptor. Separated from the drum 10.

An opening 23a is formed approximately in the center of the support plate 23, and the support shaft 25 is inserted through the opening 23a. A side portion of the press plate 31 is rotatably fitted to each end of the support shaft 25 located within the opening 23a. The pressing plate 31 extends in a direction away from the photosensitive drum 10 and is located above the support plate 23 .

An engaging protrusion 34 is provided on the end surface of the press plate 31 on the side where the weight 32 is disposed, and one end of a wire 35 is locked to the engaging protrusion 34 . The other end of the wire 35 is connected to the housing 2
Plunger 36 of a solenoid 36 arranged on the top surface of 1
It is locked on a. The solenoid 36 is.

In the off state, the plunger 36a is pulled downward by the weight 32. Then, the pressing plate 31 rotates downward due to the weight of the nine weights 32, comes into contact with the upper part of the side edge of the opening 23a of the supporting plate 23, and presses the supporting plate 23 downward. As a result, the blade 22 is pressed against the surface of the photoreceptor drum 10, and the contact pressure against the surface of the photoreceptor drum 10 is increased.

Conversely, when the solenoid 36 is turned on, the plunger 36
a pulls the weight 32 upward to rotate the press plate 32 upward so that the press plate 32 does not come into contact with the support plate 23; When the solenoid 36 is turned on, the pressing plate 31 is rotated to a position where it does not come into contact even when the support plate 23 is rotated, because the solenoid 28 is turned on.

Each solenoid 28 and 36 provided in the cleaning device 20 is controlled by a control section 40, as shown in FIG. The control unit 40 includes a start button 41. for starting the copying operation. and the output of a drum position detector 42 that detects the rotational position of the photoreceptor drum IO. The drum position detector 42 is.

For example, an encoder attached to the photoreceptor drum 10 is used to detect a predetermined position on the surface of the photoreceptor drum 10 when the photoreceptor drum 10 rotates.

The operation of such an electrophotographic copying machine will be explained based on the flowchart shown in FIG.

(1) First, place the original to be copied on the original placing table 12, and turn on the start switch 41. At this time, if the number of copies is 2 or more, set the number of copies by operating a number setting key (not shown).

When the start switch 41 is turned on, the solenoid 28
is turned off, and the solenoid 36 is turned on. When the solenoid 28 is turned off, the support plate 23 in the cleaning device 20 is rotated by the weight 26.
The blade 22 is brought into contact with the surface of the photoreceptor drum 10 with a predetermined pressure. In this case, by turning on the solenoid 36,
The plunger 36a is pulling the weight 32 upward, and the pressing plate 31 is not in contact with the support plate 23.

(2) In this state, the main motor is driven. Driven by the main motor, the optical system 11 starts moving and the photosensitive drum 10 starts rotating.

The counter of the drum position detector 42 is
0 starts counting the pulses emitted from the encoder mentioned above. The optical system 11 first exposes the image quality inspection original 13 to the surface of the photoreceptor drum 10 to form an electrostatic latent image thereon, and then exposes the original for copying on the original mounting table 12.
The surface of the photoreceptor drum 10 adjacent to the electrostatic latent image of the original for image quality inspection is exposed to form an electrostatic latent image. These electrostatic latent images are sequentially developed with toner in the developing device 15, and the toner density of the toner image for two image quality inspections is measured by, for example, a toner density detector (not shown). The toner image for image quality inspection is fed to a position opposite the cleaning device 20 without being transferred from the surface of the photoreceptor drum 10 to a transfer paper by the transfer device 16.

(3) When the number of pulses counted reaches a predetermined number.

The drum rotation position detector 42 is connected to the photosensitive drum 10.
When detecting that the toner image of the image quality inspection document on the front surface has reached a predetermined position near the cleaning device 20, the control section 40 turns off the solenoid 36. As a result, the press plate 31 is rotated downward by the double weight 32 and comes into contact with the support plate 23, and the support plate 23 is also pressed by the weight 32. Due to this pressure.

The blade 22 in contact with the surface of the photoreceptor drum 10 presses the surface of the photoreceptor drum 10 even more strongly. At this time, a timer within the control unit 40 is operated. With the blade 22 strongly pressing the surface of the photoreceptor drum 10.

The photosensitive drum 10 is rotated. Along with its rotation.

The toner image for image quality inspection reaches a position opposite the cleaning device 2o, and is scraped off from the photoreceptor drum 10 by the blade 22 that strongly contacts the surface of the photoreceptor drum 10.

(4) Time required for the toner image for image quality inspection on the surface of the photoreceptor drum 10 to pass through the contact position of the blade 22.

When the timer clocks, solenoid 36 is turned on.

The plunger 36a pulls the weight 32, and the pressing plate 31
is separated from the support plate 23. This allows blade 2
2, the pressing force by the weight 32 of the pressing plate 31 is released and 9
The weight 26 is brought into contact with the surface of the photosensitive drum 10 only by its own weight. On the other hand, the toner image for copying formed on the surface of the photoreceptor drum 10 is transferred onto a transfer paper by a transfer device 16, and the transfer paper is transferred to the photoreceptor drum 10 by a separation device 17.
It is separated and transported. After the toner image has been transferred, the surface of the photosensitive drum 10 is cleaned by a cleaning device 20.
is fed to the opposite position.

As described above, only the weight of the weight 26 causes the blade 22 that comes into contact with the surface of the photoreceptor drum 10 to scrape off the toner remaining on the surface of the photoreceptor drum 10 .

(5) If the set number of copies is 1, perform the following (7).

(6) If the set number of copies is 2 or more.

Repeat steps (2) to (4) above to make the set number of copies. When the set number of copies have been completed, the process proceeds to the first step (7).

(7) When the surface of the photosensitive drum 10 on which the toner image for copying has been formed passes the contact position of the blade 22, the drive of the main motor is stopped, the solenoid 28 is turned on, and the plunger 28a pushes the weight 26. The blade 22 is pulled away from the surface of the photoreceptor.

(8) This completes the copying process, and the electrophotographic copying machine enters the standby state.

Although the embodiment has been described above in which a toner image for image quality inspection is formed for each copying operation even when the number of copies is two or more, the control mode of the image forming apparatus of the present invention is not limited thereto. For example, even in such continuous copying, if the image is formed and toner density control is performed only during the first copying operation, steps (2) to (7) above are performed only during the first copying operation. .

(Effects of the Invention) As described above, when scraping off the toner image for image quality inspection formed on the photoreceptor, the electrophotographic copying machine of the present invention increases the blade pressure applied to the surface of the photoreceptor and scrapes off the transfer paper. When scraping off the toner remaining on the photoconductor surface after being transferred to the photoconductor, the blade pressure applied to the photoconductor surface is kept low, so that the toner image for image quality inspection is reliably removed from the photoconductor and the copied image is removed. There is no risk of having a negative impact on the Since the blade pressure is increased only when scraping off the toner image for image quality inspection, frictional deterioration of the photoreceptor can be suppressed, resulting in a longer lifespan of the photoreceptor and the risk of an increase in the amount of sliding contact. do not have.

4. ``Panasonic'' Figure 1 is a sectional view showing an example of an electrophotographic copying machine of the present invention;
Figure 2 is a sectional view of the main part, Figure 3 is a sectional view taken along the line ■-■ in Figure 2, Figure 4 is a block diagram of the control circuit, and Figure 5 is a sectional view of the main part.
The figure is a flowchart for explaining the operation.

10... Photosensitive drum, 11... Optical system, 13.
・・Document for image quality inspection, 20 ・・Cleaning device, 2
2...Blade.

23...Support plate, 26.32...Weight, 28.
36...Solenoid.

31...pressing machine.

that's all

Claims (1)

[Claims] 1. After the toner image formed in a predetermined area on the photoreceptor is transferred to transfer paper, the toner remaining on the photoreceptor is removed by bringing a blade into contact with the photoreceptor, and , an image forming apparatus capable of forming a toner image for image quality inspection in an area other than a predetermined area on the photoconductor, the toner image for image quality inspection being formed by increasing the contact pressure of the blade against the photoconductor. , an image forming apparatus configured to scrape off.