JPH06202405A - Image forming device - Google Patents

Abstract

PURPOSE:To rapidly detect the condition where an image carrier is defectively cleaned by means of a cleaning means in an image forming device having the image carrier to be repeatedly used. CONSTITUTION:As to the image forming device provided with the image carrier endlessly moving and repeatedly used, an electrostatic charging means electrostatically charging the image carrier, the latent image forming means of the image carrier, a developing means visualizing a latent image, and the cleaning means cleaning the image carrier; a potential detecting means 12 detecting the potential distribution of the image carrier, or a density detecting means 12 detecting density distribution is provided, a deciding means (CPU) 14 deciding whether the maintenance of the cleaning means is required or not basing on the detection result is provided, and a warning means 17 warning the maintenance is required when the means 14 judges that the maintenance is required is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a copying machine, a printer,
The present invention relates to an image forming apparatus using an electrophotographic method used for a facsimile or the like.

[0002]

[Prior art]

<Prior Art Example 1> In an image forming apparatus to which an electrophotographic technique is applied, an image carrier is repeatedly used through the steps of charging, development, transfer, cleaning and the like. Therefore, the surface of the image carrier must be kept clean in each image forming step. Therefore, when the cleaning operation is incomplete or the cleaning performance deteriorates with use, the cleaning state becomes incomplete, so-called cleaning failure occurs, and the quality of the copy image is significantly deteriorated.

<Conventional Example 2> Conventionally, there is a method of forming a final image by transferring toner onto a transfer material and fixing the image by a fixing device, and then transferring and fixing the toner onto the same transfer material again or a plurality of times. There is an image forming apparatus such as a copying machine used.

Such methods are roughly classified into two types, "double-sided" and "multiplexed".

Double-sided is a method in which toner is transferred onto the surface opposite to the surface on which toner has been once transferred to form an image on both sides of the paper. On the other hand, multiplex is a method of forming an image by transferring toner of a color different from that of the first time on the same surface as the surface on which the toner is once transferred.

FIG. 23 shows an embodiment of a conventional copying machine adopting such a method. In FIG. 23, 101 is a photosensitive drum which is an electrostatic latent image carrier, rotates in the direction of arrow a, and the surface of the photosensitive drum is uniformly charged by the primary charger 102. When reading the placed document, a latent image is written through the mirror groups 131, 132, 133. Reference numeral 141 denotes a developing device, which develops the electrostatic latent image created in this manner with toner by a predetermined method. The developed image thus developed is transferred onto the paper, which is a transfer material, by the transfer charger 105. The transferred paper is further conveyed to the fixing unit and fixed to the fixing rollers 171, 17
After being fixed by 2, the roller groups 191, 192 are again provided.
Is conveyed to a transfer unit for multi-sided or double-sided image formation, and for example, the developed image visualized by the developing device 142 is transferred onto the paper and fixed again on the fixing roller 17
After being fixed by 1, 172, the sheet is discharged to the discharge section 111. The remaining toner that has not been transferred is cleaned by the cleaning blade 106 and stored as waste toner.

<Conventional Example 3> In the above-mentioned Conventional Example 2, the above-mentioned problem is more severe in the "multiple" image formation in which the fixed toner image surface again contacts the surface of the photosensitive drum. In other words, when forming a “double-sided” image, the surface that comes into contact with the photosensitive drum again is the toner-free transfer material itself, and as this transfer material, a large amount of paper absorbs oil and almost no oil is present on the surface. While it does not appear, during "multiplex" image formation, there is toner that has been melted and smoothed by the fixing device on the surface that contacts the surface of the photosensitive drum again. This is because it is easy to hold on the surface, and if it is strong, the amount transferred to the photosensitive drum also increases.

<Prior art example 4> Further, a sheet-shaped transfer material, mainly paper, is brought into contact with the surface of the image carrier on which a transferable toner image is formed, and the toner image is electrostatically transferred to the transfer material. In a known image forming apparatus that repeats the step of separating the transfer material from the image carrier after the transfer, the residual toner that does not contribute to the transfer and remains on the surface of the image carrier even after the transfer material is separated is removed each time. There is a need.

As a residual toner removing means for this purpose, various means have been proposed and implemented, but one edge of a plate-like cleaning blade made of an elastic material such as urethane rubber is pressed against the image carrier. It is well known that such a device that scrapes off the residual toner is widely used because it has a simple structure, is small and compact, and has an excellent toner removing function.

However, even if such a cleaning means is used for a long period of time, the toner accumulated in the edge portion is solidified without dropping and the blade is lifted to lower the cleaning function. However, it is unavoidable that adhesion and fusion may be caused to cause deterioration of image quality and cause various inconveniences.

As a means for removing the deposits on the surface of the photoreceptor, an elastic roller having a sponge layer coated with elastic rubber is known. The elastic roller is particularly effective in removing products, paper dust, and the like due to corona discharge of the charger, which causes image deletion under high humidity. However, since the elastic roller is strongly pressed against the surface of the photoconductor and rubs against the surface, streaking occurs in the circumferential direction of the photoconductor, and streaks occur in the copy image.
After all, it could cause image deterioration.

In order to avoid such an inconvenience, there has been proposed a cleaning blade or an elastic roller configured to reciprocate in its longitudinal direction with an appropriate stroke. By this method, a kind of stimulus is applied to the edge of the cleaning blade to prevent the toner from being accumulated and the foreign matter from being attached. Further, in the case of an elastic roller, it is effective in preventing streaking in the circumferential direction of the photoconductor. For example, a cleaning blade reciprocating in the longitudinal direction of the image bearing member is disclosed in JP-A-62-105181.
There is an issue. However, since the repeated rubbing of such short-time reciprocating motion is applied to the surface of the image bearing member for a long period of time, the surface property of the image bearing member is deteriorated, which adversely affects the latent image formation. Causing a decline.

Further, when such a cleaning blade or an elastic roller is reciprocated, it is unavoidable to give vibrations to the photoconductor or the like, especially when reversing the movement direction, and the image quality may be deteriorated due to deviation or the like. . Further, particularly when a latent image is formed by scanning the surface of the photoconductor with minute spots of laser light as in a laser printer, a digital copying machine, a digital color copying machine, etc., the spot position is blurred and the latent image is formed. The image is often disturbed and the image quality is deteriorated.

Particularly in a copying machine such as a full-color copying machine, in which each color is developed on a photosensitive member several times and the toner image of each color is transferred to a transfer material held on a transfer material carrier (hereinafter referred to as a transfer drum) each time. The vibration caused by the reciprocating motion of the cleaning blade and the elastic roller caused the image quality deterioration due to the transfer deviation.

<Prior Art Example 5> FIG. 36 shows an example of a conventional color electrophotographic copying apparatus.

According to the color electrophotographic copying apparatus 401a of this embodiment, the photosensitive drum 406 which is an image carrier is rotatably supported so as to rotate in the direction of the arrow, and the image forming means is arranged around it. That is, the photosensitive drum 406 is
A light image uniformly charged by the primary charger 407 and color-separated by an exposure unit such as a laser beam exposure device or a light image 408 corresponding to the color image is irradiated to form an electrostatic latent image on the photosensitive drum 406. To do. Photosensitive drum 4
The electrostatic latent image on 06 is a visible image in each color developing device 427,
That is, a toner image is formed.

The developing device 427 includes four developing devices 42 for separately storing four color developers, that is, a magenta color developer, a cyan color developer, a yellow color developer and a black color developer.
It is composed of 7M, 427C, 427Y and 427BK. The developing device 427 develops an electrostatic latent image on the photosensitive drum 406 by bringing a desired developing device into contact with and away from the outer peripheral surface of the photosensitive drum 406.

Here, each color developer will be described. First, for the magenta, cyan, yellow, and black developers that are color developing devices, a two-component developer including a magnetic carrier and a low-melting point non-magnetic toner described later is used.

In such a two-component developer, the weight ratio of toner (Tg) to carrier (Cg) is T / T + C × 10.
They are mixed and used in a ratio of 0 = 5%.

The developer is opposed to the photosensitive drum, and only the toner flies on the drum due to the DC electric field and the alternating electric field to form a desired image.

In the conventional example, the exposure has an intensity of 256 steps from OOh to FFh with respect to exposure for image formation, and the amount of such light is changed to determine the amount of toner on the drum.
That is, the final image density is changed.

That is, the maximum amount of toner adheres when the exposure amount is FFh, and the toner does not adhere when the exposure amount is OOh.

The toner image on the photosensitive drum 406 is transferred onto a transfer material P carried by a transfer device 413 (hereinafter referred to as a transfer drum) and conveyed in the direction of the arrow in the figure.

The transfer material P is, as shown in FIG.
The registration roller 428 sends the image in synchronization with the image. It has a transfer material adsorbing means for adsorbing and holding the transfer material P fed to the transfer device 413 to a transfer sheet 434 attached to the outer peripheral surface of the transfer device 413. The transfer material adsorbing means is provided inside the transfer drum 413 and is provided outside the transfer drum 413, and an adsorbing charging device 423 that applies a charge having a polarity opposite to that of the toner image on the photosensitive drum 406 to the back surface of the transfer sheet 434. And a conductive roller 424 that is mounted. The conductive roller 424 is grounded, serves as an opposite electrode of the attraction charger 423, and has a function of injecting charges into the transfer material P and electrostatically adsorbing the transfer material P to the transfer sheet 434. The conductive roller 424 is arranged such that the gap between the conductive roller 424 and the transfer sheet 434 is 0 to 100 μm when attracted.

When continuous copying is designated by the operation panel (not shown) and the length of the transfer material in the conveying direction is less than half the length of the peripheral length of the transfer drum 413 minus the width of the connecting portion. The second transfer material is continuously fed to the first transfer material, and the second transfer material is attracted to the transfer sheet 434 at a position symmetrical to the first transfer material. That is, two transfer materials are simultaneously adsorbed on the transfer sheet 434 and conveyed. This allows
A copying speed about twice as high as that obtained when a copying operation is performed by adsorbing only one sheet on the transfer sheet 434 is obtained.

In order to transfer the first color developer, such as magenta toner, on the photosensitive drum to the first transfer material, a transfer charger 414 is used on the rear surface of the transfer sheet 434 to charge the toner of the opposite polarity. give. Then again
The same latent image is formed, the toner of the first color is developed on the photosensitive drum 406, and the toner of the first color is similarly transferred to the second transfer material. By the time the first transfer material reaches the position of the conductive roller 424 for the second time, the conductive roller 424 is released, and the transfer toner image is not disturbed, for example, the transfer sheet 43.
It is separated from 4 by 2 mm or more. The second color toner image (here, cyan color) formed on the photosensitive drum in synchronization with the first color transfer material onto which the first color toner is transferred is transferred by using the transfer charger 414. To do.

Similarly, the second color toner image is transferred to the second transfer material. Similarly, four color toners are transferred to the two transfer materials. After the transfer process is completed, a pair of AC corona dischargers 415 and 416 opposed to each other with the transfer sheet 434 interposed therebetween in order to weaken the attraction of the transfer material to the transfer sheet 434.
Is used to remove the charge, and the separation claw 418 separates the transfer sheet from the transfer drum.

Further, in order to prevent image disturbance due to peeling discharge that occurs when the transfer material and the transfer sheet are separated, it is preferable to perform AC corona discharge using the corona discharger 417.

When the length of the transfer material in the conveying direction is longer than that described above, the transfer sheet 43 is placed at the same position as the front end of the first transfer material regardless of whether it is a single copy or continuous copy.
Then, the same transfer / separation process as in the case of the first transfer material is performed. After the completion of the transfer / separation process, the transfer material is sent to the fixing device 426 via the conveyor belt 425.

The transfer material P is passed between the fixing roller 451 and the pressure roller 452, so that the toner image is fixed on the transfer material P by heat and pressure of the roller.

On the other hand, the transfer material P is transferred by the transfer charger 414.
Although toner is transferred onto the surface to form an image, a part of the toner still remains on the photosensitive drum and circulates. The toner is cleaned by the cleaning device 430. The cleaning device 430 is supported by a blade 431 made of urethane rubber or a blade support plate 432 whose surface is appropriately coated with a highly lubricious substance such as nylon, and the blade edge is applied to the photosensitive drum in a counter shape as shown in FIG. By doing so, the toner on the photosensitive drum is efficiently and completely removed.

After that, the photosensitive drum circulates again to the image forming operation, but the transfer material P is fixed by the fixing device after being separated from the transfer drum, and is discharged to the outside of the machine to complete a series of copying operations. .

The developer used in such a color electrophotographic copying apparatus, especially the color toner, will be described.

In the formation of a multi-color image or a full-color image, by using a sharp melt toner, the color reproduction range of the copy can be widened and a color copy faithful to the original can be satisfactorily obtained.

The toner is prepared by melt-kneading, pulverizing and classifying a toner forming material such as a binder resin such as polyester resin or styrene-acrylic ester resin, a colorant (dye or sublimable dye), a charge control agent. Manufactured. If necessary, various external additives (eg, hydrophobic colloidal silica) are added to the toner.

In view of fixing property and sharp melt property, it is particularly preferable that the color toner uses a polyester resin as a binder resin. As the sharp melt polyester resin, a polymer compound having an ester bond in the main chain of a molecule synthesized from a diol compound and a dicarboxylic acid is exemplified.

In particular, the following equation

[0038]

[Chemical 1]

(Wherein R is an ethylene or propylene group, X and Y are each a positive integer of 1 or more, and X is
The average value of + Y is 2 to 10. ), A bisphenol derivative represented by the formula (1) or a substituted product thereof is used as a diol component, and a divalent or higher carboxylic acid, an acid anhydride thereof or a lower alkyl esterified carboxylic acid (eg, fumaric acid,
A polyester resin obtained by at least copolycondensation of maleic acid, maleic anhydride, phthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid) as a dicarboxylic acid has sharp melting characteristics, and is therefore more preferable. The softening point of the polyester resin is 75 to 150 ° C., preferably 80.
~ 120 ° C is good. FIG. 37 shows the softening characteristics of the toner containing the polyester resin as the binder resin.

The method of measuring the softening point will be described. Flow tester CFT-500A type (manufactured by Shimadzu Corporation).
Using a die (nozzle) with a diameter of 0.2 mm and a thickness of 1.
With an extrusion load of 20 kg as 0 mm, the initial setting temperature is 7
After the preheating time of 0 ° C. and the preheating time of 300 seconds, when the temperature is increased at a constant rate of 6 ° C./min, the plunger drop amount-temperature curve (softening S-shaped curve) of the toner to be drawn is obtained. 1 sample toner
Plunger cross-sectional area of 1.
It is set to 0 cm ² . The softened S-shaped curve becomes a curve as shown in FIG. As the temperature rises at a constant rate, the toner is gradually heated and starts to flow out (plunger descending AB). When the temperature is further raised, the melted toner largely flows out (B-
C-D) Plunger descent stops and ends (D-
E).

The height H of the S-shaped curve indicates the total outflow amount, and H /
The temperature T ₀ corresponding to point C of 2 indicates the softening point of the sample (eg toner or resin).

Whether or not the toner and the binder resin have a sharp melt property can be determined by measuring the apparent melt viscosity of the toner or the binder resin.

A toner or a binder resin having a sharp melt property means that when the apparent melt viscosity is 10 ³ poise, the temperature is T ₁ , and when the apparent melt viscosity is 5 × 10 ² poise, the temperature is T _{2. 1 = 90~150 ℃ | ΔT | =} | T 1 -T 2 | = 5~20 refers to satisfy the condition of ° C..

The sharp melt resin having these temperature-melt viscosity characteristics is characterized in that the viscosity is extremely sharply lowered when heated. Such a decrease in viscosity causes a proper mixing of the uppermost toner layer and the lowermost toner layer, and also sharply increases the transparency of the toner layer itself, which enables good subtractive mixing.

[0045]

[Problems to be Solved by the Invention]

<Problem 1> However, in the first conventional example, it is difficult to predict the occurrence of cleaning failure, and it often occurs suddenly. As a preventive measure, it is inconvenient for the service person to constantly monitor, and the user has no choice but to stop copying, and by providing the cleaning mechanism with settings for maintaining cleaning performance for a long time, There is a drawback that it accelerates abrasion and deterioration of the image carrier, for example, the photoreceptor.

A first object of the present invention is to provide a warning display when a cleaning failure occurs and immediately perform maintenance. Alternatively, another object of the present invention is to provide an image forming apparatus capable of returning a machine to a normal state by performing a repair operation.

<Problem 2> Further, oil is applied to the surface of the fixing roller used in the image forming apparatus as in the second conventional example. This is an essential technique that is performed in order to extend the life of the fixing roller itself and prevent offset of the toner to be fixed onto the roller. Therefore, a small amount of oil is naturally applied to the fixed paper. Therefore, "double-sided" and "multiple"
Especially when a plurality of images are continuously formed, the oil adheres to the surface of the photosensitive drum. Therefore, if you try to perform normal image formation after that, the toner adheres to the area that is originally a white background due to the adhesive force of the oil and appears as fog, and on the other hand, to the area that is originally a solid area due to the adhesive force of the oil. However, there is a problem in that the toner is not sufficiently transferred from the drum onto the paper to form a pale image.

It is a second object of the present invention to provide an image forming apparatus which can solve the above problems and can properly remove oil on the drum to obtain a good image.

<Problem 3> Further, in Conventional Example 3, the fixing roller used in the image forming apparatus is generally coated with oil on its surface. This is an essential technique that is performed in order to extend the life of the fixing roller itself and prevent offset of the toner to be fixed onto the roller. Therefore, a small amount of oil is naturally applied to the fixed paper. Therefore, "both sides"
When the "multiple" image formation is continuously performed on a plurality of sheets in particular, oil adheres to the surface of the photosensitive drum. Therefore, if you try to perform normal image formation after that, the toner adheres to the area that is originally the white background due to the adhesive force of the oil and appears as fog, while the area that is originally the solid area is also affected by the oil's adhesive force. However, there is a problem in that the toner is not sufficiently transferred from the drum onto the paper to form a pale image.

A third object of the present invention is to solve the above problems and provide an image forming apparatus in which toner is preferably transferred onto a transfer material to obtain a good image.

<Problem 4> In view of the problems of the prior art example 4,
A fourth object of the present invention is to prevent the vibration of the image carrier and the deterioration of the surface of the image carrier due to it while keeping the advantage of reciprocating the cleaning means with respect to the image carrier. An image forming apparatus is provided, and a good image without image blur is obtained by preventing the occurrence of vibration of the image carrier and surface deterioration of the image carrier as described above.
An object of the present invention is to provide an image forming apparatus capable of effectively utilizing the characteristics of the apparatus capable of improving the durable image quality.

<Problem 5> Further, the prior art example 5 has the following drawbacks.

That is, a certain amount of toner remains on the photosensitive drum after the transfer for the amount of time during which normal image formation is performed. This is done by transferring 100 toner on the photosensitive drum.
Although it is intended to be transferred onto the transfer material, in reality, about 5% of residual toner exists.

Therefore, the toner is always present at the portion of the cleaning blade that contacts the photosensitive member.

Although the toner present to some extent serves as a lubricant between the cleaning blade and the photoconductor, good cleaning is always performed. However, when the amount of such toner decreases, the lubricity deteriorates and the cleaning blade rotates on the photoconductor. The toner may turn in the direction, or cause a so-called chattering phenomenon while slightly vibrating on the photosensitive member, and the toner may not be cleaned.

Particularly, in the color copying machine as in this example, the so-called idle rotation in the sense of adjusting the drum potential and adjusting the transfer sheet state by the pre-rotation and post-rotation of the copy is increased. The phenomenon is particularly likely to occur.

Conventionally, the toner is always present between the cleaning blade and the photosensitive member, and there is a mode in which the black toner is intentionally attached during the image formation in order to protect the lubrication state. Was being supplied.

This is because in the laser scanning system as in this example, it is possible to supply black toner in the interval according to the image forming timing, and the conventionally known light for exposing the original image is directly transmitted to the drum. It is also possible to irradiate with a method such as sticking a black patch on the platen.

As described above, the cleaning blade was not reversed, and the toner did not slip through due to chattering or the like.

However, since the black toner is used, in such a method, the mixing ratio of the toner and the carrier of the black developing device (hereinafter referred to as T / C ratio) as a full-color image fluctuates every time a black image in the cleaning band is output, It has a drawback that the blackness (coloration) of a black copy image or a full-color image varies.

The use of the black toner for cleaning in this manner is because such a technique comes from the technique in the conventional black-and-white copying machine, and also performs the black-and-white in the full-color copying machine. Therefore, because the hopper for storing toner is large, it is possible to replenish one after another even if the black toner is consumed excessively. However, recently, there is a tendency to reduce the size of the multicolor image forming apparatus, and accordingly, it is difficult to take a large space in the hopper portion, and it is difficult to configure a hopper for a specific toner to be large. The hopper corresponding to the toner needs to have the same capacity.

A fifth object of the present invention is to solve the above problems and to provide an image forming apparatus capable of obtaining a good image with little color change.

[0063]

Means for Solving the Problems and Actions In order to achieve the above-mentioned objects, the means for solving by the present invention are as described in the claims of the claims, and the actions thereof are as follows.

According to the means of the first to fifth aspects, the detection means for detecting the cleaning state of the surface of the image bearing member (hereinafter referred to as "photoreceptor") is provided, and when the cleaning failure is detected, a warning is issued or a repair operation is performed. Is automatically performed to restore the normal state, and in order to more reliably judge the certainty of diagnosis and whether the state after repair is normal, a cleaning failure check image is formed on the surface of the photoconductor and the judgment is made again. Try to do it.

Further, according to the means of claims 6 to 8, a transfer device for transferring the photosensitive drum and the toner image developed on the photosensitive drum onto the transfer material at a transfer portion which is a re-proximity portion of the photosensitive drum, In an image forming apparatus having a fixing device for fixing the toner on the transfer material, the toner on the photosensitive drum is transferred onto the transfer material, and the transfer material passes through the fixing device so that the toner is removed. After fixing and forming an image, when toner is transferred onto the transfer material again or a plurality of times to form a so-called "double-sided" / "multiplexed" image, it takes a longer time than at least one-sided image formation. The oil on the photosensitive drum is completely removed by idling the photosensitive drum.

According to the ninth to twelfth means, a photosensitive drum, and a transfer device for transferring the toner image developed on the photosensitive drum onto the transfer material at a transfer portion which is a re-proximity portion with the photosensitive drum. An image forming apparatus having a fixing device for fixing the toner on the transfer material, the toner on the photosensitive drum being transferred onto the transfer material, and the transfer material passing through the fixing device When the toner is transferred onto the transfer material again or a plurality of times after the image is fixed and the so-called "double-sided" / "multiplexed" image is formed, at least one-sided image formation is performed more than once. The conventional problems can be solved by increasing the consumption amount of the toner developed in the image area.

According to the thirteenth to fifteenth means,
A latent image forming means for forming a latent image on the surface of the moving image carrier,
Developing means for developing the latent image formed by the latent image forming means, cleaning means for cleaning the surface of the image bearing body by contacting the image bearing body, and reciprocating the cleaning means in the longitudinal direction of the image bearing body. In an image forming apparatus having reciprocating means for controlling and reciprocating means for controlling the operation of the reciprocating means, the control means image-carries the reciprocating state of the cleaning means with respect to the image carrier by the reciprocating means. While the latent image is formed on the body, the sliding direction of the cleaning means with respect to the longitudinal direction is not changed to prevent the vibration caused by the movement of the cleaning means.

Further, according to the means of claim 16, the defect in the conventional example is eliminated, yellow, magenta, cyan or black is used as a color former, and an image is formed on the image carrier with the color former. In a multi-color image forming apparatus equipped with a cleaning device that removes the color former on the image carrier after transfer to the transfer material, a single color drum rotation of the color former of each color onto the image carrier outside the desired image forming operation. By switching and forming for each number or the number of copies, toner consumption becomes uniform, and there is little change in tint during image formation,
Prevent problems such as blade flipping and perform good cleaning.

[0069]

EXAMPLES Examples according to claims 1 to 5 are shown in FIGS.
Will be described.

FIG. 1 is a schematic view of an image forming apparatus embodying the present invention.

Reference numeral 1 denotes a photosensitive member which rotates in the direction of the arrow. A main charger 2 uniformly charges the surface of the photoconductor, and the image exposing means 3
A latent image is formed by the developing means 6 and visualized by the developing means 6. 4 is a blank exposure means. Next, the image is transferred to the transfer material 7 by the transfer means 8, and the transfer material 7 is conveyed to the fixing means (not shown) to form a copy image.

Reference numeral 9 is a cleaning means, and 10 is a pre-exposure means, and the surface of the photosensitive member is returned to a uniform potential state, and one cycle is completed.

The surface of the photosensitive member is detected by providing the potential sensor 5 or the reflection type photo sensor 11. Either one of these may be used, or both may be used at the same time for further certainty.

<Example 1> (When a potential sensor is used) The potential sensor 5 is configured to be movable in the longitudinal direction of the photoconductor 1 so that the entire surface of the photoconductor can be checked. Indicate. Here, M is a motor, and the rotation of the screw shaft 5S by the motor M moves the potential sensor 5 in the axial direction.

FIG. 3 is a block diagram showing a main circuit configuration to which the present invention is applied. Reference numeral 12 is a detection means for checking the surface state of the photoconductor, and in this embodiment, a potential sensor or
It is a reflective photo sensor. 13 is an A / D converter connected to a potential sensor or the like, 14 is a central processing unit (CPU) as a judging means for processing input data and judging whether maintenance is necessary, and 15 is a RAM for carrying out arithmetic processing.
(Memory), 16 is a ROM (memory) storing programs for data processing methods and determination methods, and 17 is a CP
When it is determined in U14 that maintenance is necessary, it is a warning means for displaying with a display, a lamp, or the like, or a warning means for connecting to a telephone line or the like and communicating with a service base.

FIG. 4 is a flowchart of this sequence.

When the diagnosis is started, the rotation of the photosensitive member is turned on, the pre-exposure is turned on, and the main charging is turned on. Due to the main charging, the defective cleaning area is charged and the potential becomes high, so that the determination can be made. The blank exposure was turned on to lower the normal area to the bright area potential, but it is not necessary to use it if it is not necessary.

FIG. 5 shows the potential distribution when cleaning failure occurs.

The current value of the main charger was set so that the dark portion potential was 400V, and the light portion potential was 50V. Therefore,
The area free of poor cleaning is measured at 50V. From the graph, 100mm and 240 in the longitudinal direction of the photoconductor
A cleaning failure occurs at a position of ~ 300 mm. The detection potential at this time was about 120 to 200V.

At this time, for example, if a criterion of NG is set to 100 V or more, this portion is determined as a cleaning non-region.

Data was taken in at a pitch of 2 mm and the measurement length was 300 mm, that is, 150 points were measured.

FIG. 6 shows the relationship between the photoconductor potential of the machine used and the copy density. The reason why the above criterion is 100V is that the development is started from 100V.

In this way, the cleaning state is diagnosed, and in the case of NG, a message requiring maintenance is displayed on the display of the device and the user makes a serviceman call or services via the telephone line or dedicated line. Information is automatically communicated to the bases, and service personnel can respond quickly.

When the diagnosis is determined to be OK, the normal image forming process is proceeded to, and the similar diagnosis is performed at the next diagnosis.

At the time of diagnosis, the device power is turned on the first time in the morning.
If necessary, the fixing heat roller is being heated and the copying work of the user can be performed without interruption.

<Embodiment 2> When a reflection type photo sensor is used, the reflection type photo sensor 11 is installed in FIG. 1 and the amount of light reflected from the surface of the photosensitive member is read to determine the presence or absence of the developer, that is, the cleaning state. . Like the potential sensor 5, the photo sensor 11 is provided so as to be movable in the longitudinal direction of the photoconductor as shown in FIG.

FIG. 7 is a schematic diagram in which the light from the light emitting element (a) is reflected on the surface of the photoreceptor and the light receiving element (b) detects the reflected light. The block diagram is the same as FIG. 3 of the first embodiment. FIG. 8 is a flowchart.

FIG. 9 shows the same cleaning state measured as in Example 1. The vertical axis is the amount of reflected light and is set to an arbitrary scale for convenience.

Data was taken in at a pitch of 5 mm. Therefore, 60 points were measured for a measurement area of 300 mm.

Also in this case, it is possible to determine the cleaning state by providing an appropriate reference point (dotted line in the figure).

The following is the same as in the first embodiment.

Next, the case of performing repair will be described.

FIGS. 10A to 10D show the main cleaning methods currently used.

(A) is a cleaning blade (18) system (b) is a cleaning blade (18) + elastic roller (19) system (c) is a cleaning blade (18) + fur brush (20) system (d) is magnetic Brush (22) method With regard to method (c), a blade may be omitted, or a blade may be added to method (d).

FIG. 11 is a flow chart when the repair process is incorporated.

In the figure, the test pattern may be omitted in the dotted line.

N.V. in the first judgment. G. In this case, the repair operation is performed according to each cleaning mechanism. Next, a test pattern is formed and the repaired state is checked. The test pattern is not always necessary, and N. G. It is also possible to leave the cleaning failure state. However, it is better to see it from the certainty of the repair state check. Then, a determination is made, and if it is OK, the copy is possible. However, since the cleaning mechanism is in a repaired state, a warning is given that this state is in effect.

For example, communication is automatically made to the service base via a communication line, and maintenance is performed early by a service person.

Alternatively, the user may contact the service base by displaying a display on the display screen indicating that the repair is being performed.

N. G. In the case of, a warning is issued as in the first embodiment.

As described above, by providing the repair process, it is possible to quickly perform maintenance without disturbing the user as much as possible.

The test pattern may be formed at any time, not after the repair process but at the time of diagnosis. Such a flow chart is shown in FIG.

A method of repairing each cleaning mechanism will be described below.

Blade System FIGS. 13 and 14 show a method of increasing the blade pressure of the cleaning blade. An example of the flowchart is shown in FIG.

In FIG. 14A, the blade pressure spring 18 is used.
"a" is linked to the solenoid 18b and has an initial set pressure. Next, when cleaning failure is detected, the solenoid is turned on, the spring is further extended, and the blade pressure is increased.

In FIG. 14 (b), the spring is the pressure adjusting plate 18
When the cleaning failure is detected, the eccentric cam 18d is rotated by a preset angle and the blade pressure is increased. In this case, the rotation angle can be adjusted in several steps.

As another method, it is effective to accelerate the reciprocating operation of the blade, or to remove the toner and paper dust accumulated on the edge portion by cleaning the blade edge.

Edge cleaning is a well-known technique. For example, a blade may be constructed so as to be brought into contact with or separated from the surface of the photosensitive member, and the brush or thin plate may be rubbed with the edge when separated.

Cleaning / Roller System FIG. 15 shows a flow chart in the case of changing the peripheral speed of the residual toner collecting roller.

The initial set peripheral speed is V ₀ , and when the cleaning failure is detected by the diagnosis, the second peripheral speed V ₁ (V ₁ > V
₀ ), further diagnosis is performed, and if defective cleaning is detected again, the third peripheral speed V ₂ (V ₂ > V ₁ > V) is reached.
It is set to ₀ ). The above is two repair steps, but it is obvious that the number of repair steps may be increased.

It is also possible to use a conductive roller,
In the configuration in which a voltage having a polarity opposite to that of the residual toner is applied to and collected by the insulating roller as described above, the applied voltage may be increased together with the detection of the cleaning failure.

The flow is the same as in FIG.

Both the blade pressure increase and the roller peripheral speed increase (or the roller applied voltage increase) may be performed simultaneously.

FIG. 17 shows such a flow.

Another method is to increase the contact pressure of the cleaning roller to improve the recovery property from the surface of the photosensitive member.

Fur Brush System Similar to the cleaning roller system, the peripheral speed and applied voltage of the fur brush are increased to enhance the ability to collect residual toner. In addition, a collection roller 2 that collects toner from the fur brush
The voltage of 1 may be increased to enhance the cleaning effect of the fur brush.

The above combination and the combination with increasing the blade pressure are the same as described above.

The flow is the same as in FIGS.

Magnetic brush system The same as the fur brush system, such as the adjustment of the peripheral speed of the magnetic brush and the applied voltage, and the adjustment of the applied voltage of the collecting roller that collects toner from the magnetic brush.

18 and 19 show some cleaning failure test patterns.

These are blank exposures for analog machines,
With a digital machine, a latent image can be easily formed by laser irradiation, and a pattern can be formed by developing means.

In FIG. 18, a) is solid black, which is for checking the cleaning property when the residual toner is increased.
This is effective when the blade is heavily worn or when the collection ability of the roller or fur brush is deteriorated.

The line b) has a line shape, and toner is intermittently sent. In the cleaning blade method, the coefficient of friction between the blade and the photoconductor greatly contributes to the cleaning property. For example, when the coefficient of friction is high, the load on the blade becomes large and the stable contact state may not be maintained.

Since toner generally serves as a lubricant, this is a method of checking by intermittently changing the blade.

Step c) is also effective when the coefficient of friction of the blade is high, and since the amount of cleaning toner is small, it is easy to create a state where the blade is in poor contact.

D) and e) are patterns for forming an image in a part of the image forming area. The pattern may be not only solid black but also b) or c).

After all, it is effective when the coefficient of friction is high,
This is a method in which lubrication is given only by a part of the toner, and the balance of the contact state of the blade with the photosensitive member is lost and the check is performed.

In particular, this method is effective as an equalizing method as shown in FIG. 20 as a blade holding method. Since this system is configured so that it can freely rotate around the Z axis, it can be naturally brought into contact with the photoconductor in a state of being balanced in the blade longitudinal direction. On the other hand, if the coefficient of friction is high, the balance is likely to be lost, and particularly the balance around the y axis is easily lost, and cleaning failure is likely to occur. This is an effective pattern for such a system.

FIG. 19 shows a pattern in which the pattern of FIG. 18 (d) is alternately formed at both ends of the blade and the balance of both ends is alternately broken to check.

Next, FIG. 22 shows an embodiment according to claims 6 to 8.
To 24 will be described.

<Embodiment 3> FIG. 22 is an enlarged schematic view around the photosensitive drum in the image forming apparatus for explaining the effect of the present invention.

In FIG. 22, not all the toner visualized on the photosensitive drum is transferred onto the transfer paper by the transfer charger 105, but a little like 181 is attached on the photosensitive drum 101. The cleaning blade 1 is conveyed as it is to the cleaning unit 110, which is the contacting portion between the cleaning blade 106 and the photosensitive drum 101, and the cleaning blade 1
It is scraped off by 06. The scraped toner is received by the scooping sheet 162 so as not to spill, and is collected in the cleaner 161.

At this time, the oil adhering to the photosensitive drum adheres to the toner particles 108 accumulated in the cleaning unit 110 when passing through the cleaning unit 110, and is cleaned together with the adhered toner particles 108 from the photosensitive drum 101. To be done. The following experiment was conducted to confirm this.

<Confirmation Experiment> It was attempted to scrape off the oil adhering to the photosensitive drum only with the cleaning blade 106 without placing any toner on the photosensitive drum, but it could not be sufficiently removed. On the other hand, the cleaning unit 110
When the toner was accumulated on the surface of the photosensitive drum and cleaned by the cleaning blade 106, the oil adhering to the photosensitive drum was completely removed.

According to this experiment, the oil adhering to the photosensitive drum permeates (adheres) to the toner particles accumulated in the cleaning section, and the toner particles are removed by the cleaning blade, and are removed together with the toner. The mechanism of oil removal is easily imagined.

Therefore, by increasing the number of idle rotations of the photosensitive drum, the oil adhering to the photosensitive drum becomes more likely to adhere to the toner particles, so that the oil cleaning performance is improved.

Based on the above idea, "multiplex"
During post-rotation when forming a "double-sided" image, the oil deposited on the photoconductor drum is increased by increasing the idling speed of the photoconductor drum by one revolution, preferably three revolutions or more, as compared with the normal single-sided image formation. Could be completely removed.

<Embodiment 4> As already described in the conventional problem, the oil is most easily attached to the photosensitive drum during the "multiplex" image formation. Therefore, it is necessary to increase the number of idle rotations of the photosensitive drum by one rotation, preferably two rotations, when forming the "multiplex" image, compared to when forming the "double-sided" image. By doing so, the effect of the present invention can be obtained. Is fully demonstrated.

<Embodiment 5> The oil cleaning property can be further improved by placing the toner on the photosensitive drum during the idle rotation as shown in the embodiment 3. This is because, as described in the oil cleaning mechanism in the third embodiment, the oil adheres to the toner and is cleaned together with the toner. Therefore, the larger the amount of toner involved in the cleaning, the higher the oil cleaning ability. Is clear. Actually, it is sufficient to develop a solid image by a desired width during idling, and by doing so, the idling time can be shortened.

<Embodiment 6> The effects of the present invention in the embodiments described above are also effective in a full-color image forming apparatus having a so-called transfer drum.

FIG. 24 is an example of such a general full-color image forming apparatus.

In FIG. 24, in the full-color image forming apparatus, a photosensitive drum 101 which is rotatably supported and rotates in the direction of the arrow is arranged, and an image forming means is arranged on the outer peripheral portion thereof. The image forming means may be any means, but in the present embodiment, the primary charging device 102 that uniformly charges the photosensitive drum 101 and the color-separated optical image or an optical image corresponding to the primary charging device 102 are irradiated to the photosensitive drum 101. An exposure unit 13 including, for example, a laser beam exposure unit that forms an electrostatic latent image thereon.
0 and a rotary developing device 140 that visualizes the electrostatic latent image on the photosensitive drum 101.

The rotary developing device 140 includes four developing devices 104 for separately accommodating four color developers of yellow developer, magenta developer, cyan developer and black developer.
It comprises Y, 104M, 104C and 104K, and a substantially columnar support which holds these four developing devices and is rotatably supported. The rotary developing device 140 conveys a desired developing device to a position facing the outer peripheral surface of the photosensitive drum 101 by the rotation of the support, develops the electrostatic latent image on the photosensitive drum 101, and performs full-color development for four colors. Is configured to be possible.

The visible image on the photosensitive drum 101, that is, the toner image is transferred to the transfer material P which is carried and carried by the transfer drum 150 which is a transfer material carrier. In this example, the transfer drum 150 is rotatably supported, and a transfer material carrying member 151 is stretched over the opening of the outer peripheral surface. As the transfer material carrying member 151, for example, a film-shaped dielectric sheet such as polyethylene terephthalate or polyvinylidene fluoride resin film is used. Further, the transfer drum 150 has a transfer material gripper 157 that holds the transfer material P fed from the paper feeding device.
Further, a transfer discharger 152, and an inner charge-eliminating discharger 153 and outer charge-eliminating dischargers 154 and 155, which form a charge-eliminating unit, are arranged inside and outside the transfer drum 150.

A process of forming a full-color image by the full-color electrophotographic copying apparatus having the above-mentioned structure will be briefly described.

The primary charging device 2 uniformly charges the photosensitive drum 101, and the exposure unit 130 irradiates the optical image E according to the image information to form an electrostatic latent image on the photosensitive drum 101. The electrostatic latent image is visualized as a toner image by the rotary developing device 140 on the photosensitive drum 101 with the resin-based toner having an average particle diameter of 8 to 10 μm. On the other hand, the transfer material P is guided by the registration roller 114 through the paper feed guide 118 in synchronization with the image to the transfer portion, which is an area where the photosensitive drum 101 and the transfer drum 150 are closest to each other. At this time, the toner image on the photosensitive drum 101 of the first color is transferred onto the transfer material P by performing corona discharge having a polarity opposite to that of the toner from the back surface of the dielectric sheet 151 by the transfer discharger 152. The transfer material P is further subjected to the required number of transfer steps, and then discharged by the discharging devices 153, 15 for static elimination.
While being subjected to static elimination by 4, 155, it is separated from the transfer drum 150 by the action of the separating claw 115, is fixed by the heat roller by the fixing device 117 by the transport belt 116, and is then discharged to the outside of the machine.

At this time, when images are to be formed on both sides of the transfer material P, the transfer material transport guide 119 is driven immediately after the fixing device 117 is discharged to guide the transfer material to the transport guide 120, and then the transfer material is transferred. Temporarily stored in the stocker 121,
An image is formed on the other surface by the above-described image forming process.

On the other hand, the surface of the photosensitive drum 101 is cleaned with residual toner by the cleaning device 160, and then subjected to the image forming process again.

The surface of the dielectric sheet of the transfer drum 150 is also made up of a fur brush or the like cleaning device 1.
After being cleaned by the action of 80 and the cleaning assisting means 181, it is subjected to the image forming process again.

At this time, when the toner is transferred to the back surface after the image on the front surface is formed, the transfer material P has the fixing oil attached to the surface (on the toner) because it has passed through the fixing roller once. The oil first transfers onto the dielectric sheet of the transfer drum, and further transfers to the surface of the photosensitive drum when the photosensitive drum and the transfer drum sheet come into contact with each other at the transfer section.

Therefore, even in the full-color image forming apparatus having the transfer drum as described above, the effect of the present invention is applied, and the rotational speed of the photosensitive drum is set at the time of double-sided formation at the time of normal single-sided image formation. More than one rotation, more preferably three rotations or more, can remove the oil adhering to the photosensitive drum.

The embodiment according to claims 9 to 12 is shown in FIG.
5, 26 will be described.

Example 7 The explanation of the effect of the present invention is as follows.
It may be explained why the oil attached to the photosensitive drum is easily removed by increasing the amount of toner on the photosensitive drum.

FIG. 25 is an enlarged schematic diagram around the photosensitive drum in the image forming apparatus for explaining the effect of the present invention.

In FIG. 25, not all the toner visualized on the photosensitive drum is transferred onto the transfer paper by the transfer charger 205, but a little like 281 is attached on the photosensitive drum 201. As it is, the cleaning blade 206 is conveyed to the cleaning unit 210, which is the contact portion between the cleaning blade 206 and the photosensitive drum 201, and the cleaning blade 2
It is scraped off by 06. The scraped toner is received by the scooping sheet 262 so as not to spill, and is collected in the cleaner 261.

However, the oil adhering to the photosensitive drum was scraped off only by the cleaning blade 6 without placing any toner on the photosensitive drum, but could not be sufficiently removed. On the other hand, when the cleaning blade 206 was used to clean the photosensitive drum after the toner was sprinkled with the toner, the oil adhering to the photosensitive drum was completely removed.

According to this experiment, the oil adhering to the photosensitive drum permeates (adheres) to the toner particles sprinkled on the photosensitive drum, and the toner particles are removed together with the toner by the cleaning blade. You can easily imagine the mechanism of oil removal called going.

Therefore, by increasing the amount of toner on the photosensitive drum, the oil adhering to the photosensitive drum becomes easier to adhere to the toner particles, and the oil cleaning performance is improved.

On the other hand, in order to prevent the cleaning blade from turning over, a method is employed in which toner is developed on the photosensitive drum during the pre-rotation, the post-rotation, or both (hereinafter, abbreviated as banding). The toner image pattern developed on the surface is to reduce the toner consumption as much as possible such as only in front and behind the photosensitive drum, and positively removes the oil adhering to the photosensitive drum. is not.

Based on the above idea, "multiplex"
The amount of toner consumed for developing on the photosensitive drum from the developing device during post-rotation when forming a "double-sided" image is approximately
50 mg / A4, preferably 100
By adding it so that it is more than mg / A4,
By adhering to the entire width of the photosensitive drum and increasing its consumption amount, the oil adhering to the photosensitive drum could be removed.

<Embodiment 8> As already described in the conventional problems, the oil is most easily attached to the photosensitive drum during the "multiplex" image formation. Therefore, the amount of toner consumption when the "multiplex" image is formed is 50 mg / A4, preferably F200, more than when the "double-sided" image is formed.
It is necessary to develop the toner on the photosensitive drum so that the amount becomes mg / A4 or more, and the effects of the present invention are sufficiently exhibited by doing so.

<Embodiment 9> In order to more effectively bring out the effect of the present invention, when a large number of "multiplexed" / "double-sided" image formations are continuously performed, the embodiment 7 is appropriately used. It suffices to perform an appropriate amount of the developing operation as performed.

The appropriate / appropriate amount changes depending on the number of images formed at that time, the paper size, and the density.
For example, the larger the number of sheets, the larger the amount of oil that adheres. Therefore, the developing operation may be performed every time an appropriate number of images are formed on the non-image portion during image formation. Also,
When the paper size is a small size such as B5 size, the oil adhering to the photosensitive drum is only the paper size, and therefore it is not necessary to waste toner, and therefore, FIG.
In the case of an analog optical system such as that described above, the shutter or the like may be operated, and in the case of a digital optical system, the laser may be operated respectively to perform the developing operation only on a necessary portion.

<Embodiment 10> The effects of the present invention in the embodiments described above are also effective in a full-color image forming apparatus having a so-called transfer drum.

FIG. 26 is an example of such a general full-color image forming apparatus.

In FIG. 26, in the full-color image forming apparatus, a photosensitive drum 201 which is rotatably supported and rotates in the arrow direction is arranged, and an image forming means is arranged on the outer peripheral portion thereof. The image forming means may be any means, but in the present embodiment, the photosensitive drum 201 is irradiated with a primary charger 202 that uniformly charges the photosensitive drum 201 and a color-separated optical image or an optical image corresponding thereto. An exposure unit 23, which is, for example, a laser beam exposure unit, which forms an electrostatic latent image on it.
0 and a rotary developing device 240 that visualizes the electrostatic latent image on the photosensitive drum 201.

The rotary developing device 240 includes four developing devices 204 for separately storing four color developers of yellow developer, magenta developer, cyan developer and black developer.
It includes Y, 204M, 204C, and 204K, and a substantially cylindrical support body that holds these four developing devices and is rotatably supported. The rotary developing device 240 conveys a desired developing device to a position facing the outer peripheral surface of the photosensitive drum 201 by the rotation of the support, develops the electrostatic latent image on the photosensitive drum 201, and performs full-color development for four colors. Is configured to be possible.

The visible image, that is, the toner image, on the photosensitive drum 201 is transferred to the transfer material P carried and carried by the transfer drum 250 which is a transfer material carrier. In this example, the transfer drum 250 is rotatably supported, and a transfer material carrying member 251 is stretched over the outer peripheral surface opening area. As the transfer material carrying member 251, for example, a film-shaped dielectric sheet such as polyethylene terephthalate or polyvinylidene fluoride resin film is used. Further, the transfer drum 250 has a transfer material gripper 257 that holds the transfer material P fed from the paper feeding device.
Further, a transfer discharger 252, an inner charge removal discharger 253 and outer charge removal dischargers 254, 255, which constitute charge removal means, are arranged inside and outside the transfer drum 250.

A process of forming a full-color image by the full-color electrophotographic copying apparatus having the above-mentioned structure will be briefly described.

The primary charging device 202 uniformly charges the photosensitive drum 201, and the exposing means 230 irradiates the optical image E according to the image information to form an electrostatic latent image on the photosensitive drum 201. The electrostatic latent image has an average particle size of 8 to 10 made of resin as a base material on the photosensitive drum 201 by the rotary developing device 240.
The micron toner makes it visible as a toner image.
On the other hand, the transfer material P is guided by the registration roller 214 through the paper feed guide 218 in synchronization with the image to the transfer portion, which is an area where the photosensitive drum 201 and the transfer drum 250 are closest to each other. At this time, a corona discharge having a polarity opposite to that of the toner is performed from the back surface of the dielectric sheet 251 by the transfer discharger 252, so that the toner image on the photosensitive drum 201 of the first color is transferred onto the transfer material P. The transfer material P is further subjected to the necessary number of transfer steps, and then discharged by the discharging devices 253, 2 for static elimination.
The transfer belt 216 is separated from the transfer drum 250 by the action of the separation claw 215 while receiving the charge removal by 54 and 255.
After being fixed by the heat roll in the fixing device 217, it is discharged to the outside of the machine.

At this time, when images are to be formed on both sides of the transfer material P, the transfer material transport guide 219 is driven immediately after the fixing device 217 is ejected to guide the transfer material to the transport guide 220, and then the transfer material is transferred. Temporarily stored in the stocker 221
An image is formed on the other surface by the above-described image forming process.

On the other hand, after the residual toner on the surface of the photosensitive drum 201 is cleaned by the cleaning device 260, it is subjected to the image forming process again.

The surface of the dielectric sheet of the transfer drum 250 is also a cleaning device 2 including a fur brush or the like.
After being cleaned by the action of 80 and the cleaning assisting means 281, it is subjected to the image forming process again.

At this time, when the toner is transferred to the back surface after forming the image on the front surface, the fixing oil, which has passed through the fixing roller once on the transfer material P, adheres particularly to the surface (on the toner). The oil first transfers onto the dielectric sheet of the transfer drum, and further transfers to the surface of the photosensitive drum when the photosensitive drum and the transfer drum sheet come into contact with each other at the transfer section.

Therefore, even in the full-color image forming apparatus having the transfer drum as described above, the amount of toner consumed for developing from the developing device onto the photosensitive drum during the post-rotation when forming an image is compared with the conventional one. Unlike the banding, the oil adhering to the photosensitive drum could be removed by increasing the total width of the photosensitive drum and its consumption amount to 100 mg / A4, preferably 500 mg / A4 or more.

Next, an embodiment according to claims 13 to 15 will be described with reference to FIGS. 27 to 34.

<Embodiment 11> FIG. 29 is a schematic side view showing a laser beam printer utilizing an electrostatic transfer process, which is suitable for applying the present invention.

The surface photosensitive layer of the image carrier 301, which extends in the direction perpendicular to the paper surface and rotates in the direction of the arrow, is uniformly charged by the primary charger 302. This charged image carrier 30
An electrostatic latent image is formed on one surface by irradiating a laser beam 303, which is converted from image information into an electric signal and modulated according to the electric signal, by a laser beam scanner. Here, an LED array, a liquid crystal shutter array, or the like may be used for light irradiation.

Toner is supplied to the latent image by the developing device 304 to visualize the latent image into a toner image.
Then, a transfer separation charger 306 is applied to the transfer material P which is conveyed by the conveyance path 305 at the same timing as the toner image.
After being transferred by the action of, the transfer material is separated from the image carrier and further conveyed to the next step along the conveying path 308.

In such a structure, the cleaning blade 309 in the cleaning device 307 arranged at the position after the transfer moves reciprocally in the axial direction (the direction perpendicular to the paper surface) while being in pressure contact with the image carrier 301. It has become.

FIG. 28 shows an example of means for reciprocating the blade, which is a cleaning device 3 shown by a chain line.
The cleaning blade 309 in 07 is supported by a shaft 310 which is biased to the left in the drawing by a spring 311 in the apparatus.

The left end of the shaft 310 is in contact with a cam 312, and the cam is driven by a motor 313 controlled by a control circuit 314 serving as a control means to drive the shaft 31.
0, therefore the blade 309 is reciprocated.

It is assumed that the above-mentioned device operates each part as shown in the sequence of FIG.

The figure shows a case where two sheets of image are continuously formed. The reciprocating movement of the blade is performed only when the apparatus is rotated forward and backward, and is stopped during image formation. . Here, the image formation refers to all the steps of latent image formation, development and transfer.

In the experiment, an amorphous silicon photoconductor of 80φ was used as an image carrier, and its peripheral speed was 180 mm /
sec, the blade pressure was 20 gr / cm, the reciprocating stroke (moving distance) was 2 mm, and the speed was 3 mm / sec.

By performing such an operation, it was possible to prevent the resolution from deteriorating and the uneven pitch in the halftone portion due to the reciprocating movement of the blade.

In FIG. 30, a cleaning blade 309 and an elastic roller 310 disposed upstream of the blade 309 in the moving direction of the photosensitive member 301 are in pressure contact with the photosensitive member 301 in the cleaning device 307. The elastic roller 310 is configured to rotate in the direction of the arrow and reciprocate in the axial direction thereof like the blade shown in the previous embodiment. The elastic roller 310 is particularly effective in removing corona products, paper dust, and the like by a corona discharger that causes image deletion under high humidity. FIG. 31 shows a sequence of reciprocating motion of the elastic roller 310. FIG. 31 shows a case where one sheet of image is formed. The elastic roller 310 is reciprocated only when the apparatus rotates forward and backward, and during image formation (latent image formation, development and transfer). Process) has stopped.

In the experiment, an 80-φ A-Si photosensitive member was used as the photosensitive member, and its peripheral speed was 180 mm / sec. The outer diameter of the elastic roller is 18φ, and it is about 160 mm when pressed against the photoconductor with a pressure of 60 g / cm per unit length of the roller.
It was rotated at a peripheral speed of / sec. The reciprocating motion of the elastic roller was set to a stroke of 2 mm and a speed of 0.5 mm / sec. The roller used was one in which a sponge layer was formed on a core metal 6φ and the surface layer was coated with urethane rubber having a hardness of 50 ° (JISA).

By performing such an operation, it was possible to prevent the deterioration of resolution due to the reciprocating movement of the blade, the uneven pitch in the halftone portion, the blurring and the like.

Here, the cleaning of the image carrier is
Although both the blade 309 and the elastic roller 310 are used, the elastic roller 310 alone can also be used.

However, the operation of the blade in the longitudinal direction on the cleaning blade image carrier in FIGS. 27, 31, 32 and 33 is different between non-image forming and image forming.
The blade reciprocates during non-image formation, but when it enters the image forming area, the sliding direction of the blade in the longitudinal direction of the image carrier is limited to a single direction, and the blade reversing operation in this area is performed. I can't. (In each drawing, the blade stops after moving by the stroke length, but is included in the partial unidirectional area.) <Embodiment 12> Referring to FIGS. 27 and 31, the reciprocation of the blade 309 or the elastic roller 310 after the transfer is completed. Although the movement is restarted, the reciprocating movement may be performed after the development is completed if the transfer deviation or the like does not occur and the image quality is not adversely affected. It is also possible to activate it. FIG. 32 is an example in which the operation is disclosed after the completion of the developing process.

<Embodiment 13> As shown in FIG. 27, the blade 309 is stopped between the image formation on the photosensitive member and the next image formation at the time of continuous copying, but if the image quality is not affected. For example, as shown in FIG. 33, the blade 9 or the elastic roller 310 may be reciprocated after the completion of the development of the first sheet until the formation of the second latent image.

Next, the transfer material is weakened by the static eliminator 320 with respect to the transfer drum 318, separated from the transfer drum 318 by the separating claw 321, and the toner image is heated by the fixing device 316.

The photosensitive member is cleaned by the cleaning blade 309 of the cleaning unit 307 for each color development. The transfer drum 318 is configured such that scattered brushes and the like are cleaned by the brush 315.

As described above, in the case of full-color copy, development and transfer are repeated for each color, and the copy is completed by superimposing four colors. Therefore, it is necessary to avoid deterioration of image quality due to blurring, etc., and transfer blurring / deviation on the transfer material, etc.

Also in this case, the image quality can be maintained by the cleaning blade 309 in the same sequence for each color as in the above-described embodiment. Of course, this copying machine is the same even if it has an elastic roller in addition to the cleaning blade 309.

<Embodiment 14> The modification of the sequence described above is such that even in the means shown in FIG. 28, the rotation of the motor is controlled by controlling the signal output of the control circuit 314 within the range of the known control means. It will be obvious that this can be easily done by changing the number.

In the above embodiment, the elastic roller 3 is used.
The pressing force of 10 on the photoconductor may be weakened during image formation rather than during non-image formation.

FIG. 34 is a schematic diagram when the present invention is applied to a full-color copying machine. A charger 302 and an exposure device 303 are arranged around the photoconductor 301, and an electrostatic latent image is formed on the photoconductor by the electrophotographic process as in the above embodiment. The latent image is developed by a developing device 304 including a plurality of developing units 304Y (yellow), 304M (magenta), 304C (cyan), and 304B (black) each having a different color developer, and on the photoconductor 301. To be visualized.

On the other hand, the transfer paper P such as the transfer paper is fed by the paper feeding means 31.
7 to the transfer drum 318. A transfer charging device 319 transfers the visualized toner image to the transfer material supported by the transfer drum. At this time, the first color is developed on the photoreceptor and the toner image is transferred to the transfer material, and then the second color is developed and transferred. ) The process of development / transfer is performed.

Further, although the digital machine in which the latent image formation is performed by the laser beam has been described, it goes without saying that the same applies to the analog machine in which the latent image is formed by the lamp.

Although amorphous silicon is used as the image bearing member in the above embodiments, amorphous silicon can be used for a long period of time because it has excellent durability. As described above, since amorphous silicon is used for a long period of time, it is suitable for the present invention in which the cleaning property is improved by reciprocating the blade or the elastic roller. However, the present invention is not limited to this, and a conventionally known photoconductor such as ZnO, CdS, Se or OPC can be used as the image carrier, or an insulating drum having no photoconductive layer may be used.

Further, although the blade and the roller are used as the cleaning means of the image bearing member in this embodiment, a brush is also applicable.

Next, an embodiment according to claim 16 will be described with reference to FIGS.

<Embodiment 15> In the present invention, toner is supplied to the cleaning unit in repeating units of yellow (Y), magenta (M), cyan (C) and black (BK), and the number of copies is reduced. The color is switched every 1250 sheets.

During the image forming operation, for example, FF level yellow is developed. The image was formed in a 5 cm × 30 cm band, and the transfer was turned off to supply toner to the cleaner.

FIG. 35 shows a state of the image portion on the drum and the yellow toner portion supplied to the cleaner.

The toner consumption was uniform for each color, and good cleaning was possible without causing problems such as blade flipping.

<Example 16> In Example 15, YM
The same effect could be obtained by reversing the color order of CK and performing with KCMY.

<Embodiment 17> Compared with Embodiment 15, 80H
Level toner was developed, image was formed on drum, transfer was turned off, and toner was supplied to the cleaner. The same effect could be obtained. <Example 18> In contrast to Example 16, toner of 80H level was developed, an image was formed on the drum, the transfer was turned off, and the toner was supplied to the cleaner. The same effect could be obtained. <Example 19> In Example 15, the FF level toner was intermittently formed on the drum. That is, Example 15
, A belt having a wide area was formed, but in the present embodiment, three toner images were formed every 1 cm.

This is because the developing device main body suffers from a problem such that the toner is not supplied in time if the FF level toner-consuming development is carried out for a long time, so that the developing device can be used in a more stable state. This is because.

In all of the above embodiments, the color of the coloring material is switched for each number of copies, but the color may be switched for every 1600 rotations of the drum.

In the above embodiment, the transfer residual toner is supplied to the cleaner by turning on the charging device. However, the same effect can be obtained without turning off the toner. The number of copies or the number of rotations of the drum can be arbitrarily selected, but is preferably a multiple of 4 so that the toner of each color is uniformly consumed.

[0214]

As described above, the effects of the present invention are as follows.

<Effect 1> According to the inventions of claims 1 to 5, when a failure is detected by providing an automatic cleaning failure diagnosis mode, a warning is displayed on the apparatus display or the service base is automatically notified by a line or the like. The information was communicated, and the service personnel were able to respond quickly.

Further, since a diagnostic pattern is formed to forcibly create a state in which cleaning failure is likely to occur and the diagnostic is performed, the certainty of the diagnostic can be increased.

Furthermore, by providing an automatic restoration process,
Defects can be temporarily avoided, and quick service support can be achieved without stopping the device and thus without annoying the user.

By providing such a step,
This enables quick service support and eliminates the need for creating an unreasonable cleaning structure, preventing unwanted damage to the photoconductor and extending the service life.

<Effect 2> According to the inventions of claims 6 to 8, when the "double-sided" / "multiplexed" image is formed, the number of idle rotations of the photosensitive drum is increased more than when the image is formed only once on one side. The oil that adheres to the photosensitive drum can be removed by using the double-sided / multi-layer image formation, and the toner adheres to the originally white area due to the adhesive force of the oil found in the conventional example, causing fog to occur. However, the problem that the area which is originally a solid part is not sufficiently transferred from the drum onto the paper to form a light image is solved.

<Effect 3> According to the inventions of claims 9 to 12, at the time of "double-sided" / "multiplexed" image formation, the amount of toner consumed in the non-image area is more than that at the time of image formation of at least one side only. By increasing the amount of oil, the oil adhering to the photosensitive drum can be removed, and even if multiple "double-sided" and "multiplex" image formation is performed continuously, the adhesive force of the oil found in the conventional example originally causes a white background area. The problem that the toner adheres to a certain area and appears as a fog, or the area that is originally a solid portion is not sufficiently transferred from the drum onto the paper to form a light image is solved.

<Effect 4> According to the thirteenth to fifteenth aspects of the present invention, when the image forming member is provided with the cleaning means, the sliding movement in the longitudinal direction is limited to a single direction when the image is formed. By suppressing the vibration of the image carrier and the acceleration of surface deterioration as much as possible, it was possible to obtain an image with improved image quality and no image blur.

<Effect 5> According to the invention of claim 16, yellow, magenta, cyan, or black is used as a color former, and an image is formed on the image bearing member by the color former and transferred to a transfer material. After that, in a multicolor image forming apparatus equipped with a cleaning device for removing the color former on the image carrier, each color former can be sequentially switched for each copy number or drum rotation number, outside the desired image forming operation. By
In image formation, there was little change in color tint, and it was possible to prevent problems such as blade flipping.

[Brief description of drawings]

FIG. 1 is a schematic view of an image forming apparatus embodying the present invention.

FIG. 2 is a diagram showing a sensor movable in a longitudinal direction of an image carrier according to the first or second embodiment of the present invention.

FIG. 3 is a block diagram showing a main circuit configuration of the present invention.

FIG. 4 is a flowchart of a diagnosis / warning procedure.

FIG. 5 is a graph in which a cleaning failure is actually detected by a potential sensor.

FIG. 6 is a graph of photoconductor potential and copy density.

FIG. 7 is a schematic diagram when a reflective photo sensor is used.

FIG. 8 is a flowchart when a reflective photo sensor is used.

FIG. 9 is a graph showing a cleaning failure when a reflective photo sensor is used.

FIG. 10 is a diagram showing an example of a typical cleaning means.

FIG. 11: Flow chart of diagnosis / repair / warning procedure

FIG. 12 is a diagram showing an example of always forming a test pattern in a flowchart of a diagnosis / repair / warning procedure.

FIG. 13 is a flowchart regarding cleaning blade pressure restoration.

FIG. 14 is a schematic configuration diagram for cleaning blade pressure restoration.

FIG. 15 is a flowchart regarding cleaning roller peripheral speed restoration.

FIG. 16 is a schematic diagram of a cleaning roller bias application configuration.

FIG. 17 is a flowchart in which blade pressure restoration and roller condition restoration are combined.

FIG. 18 is a diagram showing an example of a cleaning failure test pattern.

FIG. 19 is a diagram showing another example of the cleaning failure test pattern.

FIG. 20 is a diagram showing an example of a cleaning blade supporting system (equalizing system).

FIG. 21 is a block diagram of a main circuit configuration relating to diagnosis / repair / warning configuration.

FIG. 22 is a schematic enlarged view around a photosensitive drum for explaining a third embodiment of the image forming apparatus of the invention.

FIG. 23 is a diagram illustrating an example of a conventional image forming apparatus.

FIG. 24 is a diagram showing a sixth embodiment of the image forming apparatus of the invention.

FIG. 25 is a schematic enlarged view around a photosensitive drum for explaining a seventh embodiment of the image forming apparatus of the invention.

FIG. 26 is a diagram showing a tenth embodiment of the present invention.

FIG. 27 is a diagram showing a timing sequence according to an embodiment of the present invention.

FIG. 28 is a schematic view showing an example of the configuration for controlling the reciprocating movement of the cleaning blade according to the eleventh embodiment of the present invention.

FIG. 29 is a schematic view showing a laser beam printer to which the invention is applied.

FIG. 30 is a schematic view of an image forming apparatus in which a cleaning device has a blade and a roller according to another embodiment of the present invention.

FIG. 31 is a diagram showing a timing sequence according to an embodiment of the present invention.

FIG. 32 is a diagram showing a timing sequence according to an embodiment of the present invention.

FIG. 33 is a diagram showing a timing sequence according to an embodiment of the present invention.

FIG. 34 is a schematic view showing a full color device to which the present invention is applied.

FIG. 35 is a toner state diagram on a drum in another embodiment of the image forming apparatus of the invention.

FIG. 36 is a schematic configuration diagram of a conventional image forming apparatus.

FIG. 37 is a toner flow tester diagram.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Photosensitive member 2 ... Main charger 3 ... Image exposure 4 ... Blank exposure 5 ... Potential sensor 6 ... Developing means 7 ... Transfer material 8 ... Transfer separating means 9 ... Cleaning means 10 ... Pre-exposure 11 ... Reflective photosensor 12 ... Detecting means 13 ... A / D converter 14 ... CPU 15 ... RAM 16 ... ROM 17 ... Warning means 18 ... Cleaning blade 19 ... Cleaning roller 20 ... Fur brush 21 ... Collecting roller 22 ... Magnetic brush 23 ... Collecting roller 101 ... Photosensitive drum 102 ... Primary charging device 103 ... Optical system scanner 141, 142 ... Developing device 105 ... Transfer charging device 106 ... Cleaning blade 171, 172 ...
Fixing roller 108 ... Toner 110 ... Cleaning section 150 ... Transfer drum 151 ... Transfer sheet 180 ... Fur brush cleaner 121 ... Stocker 201 ... Photosensitive drum 205 ... Transfer charger 206 ... Cleaning blade 208 ... Toner 210 ... Cleaning section 250 ... Transfer drum 251 Transfer sheet 280 Fur brush cleaner 221 Stocker 301 Image carrier 309 Cleaning blade 310 Elastic roller 314 Control means 406 Image carrier 413 Transfer separation device 430 Cleaner

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Ryuichiro Maeyama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masakazu Eto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Ken Jojo 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (16)

[Claims] 1. An image carrier which moves endlessly and is repeatedly used, a charging unit for charging the image carrier, a latent image forming unit for the image carrier, a developing unit for visualizing the latent image, and a cleaning for the image carrier. In an image forming apparatus having a cleaning unit for performing, a potential detecting unit for detecting a potential distribution of the image carrier, or a density detecting unit for detecting a density distribution is provided,
Based on the detection result of the potential detecting means or the density detecting means, a determining means for determining whether or not the cleaning means needs maintenance is provided, and when it is determined that maintenance is required,
An image forming apparatus comprising a warning unit for warning that maintenance is required. 2. The image forming apparatus according to claim 1, wherein when the detection unit determines that maintenance is required, a repair operation is performed, and thereafter, whether the maintenance is required is determined by the detection unit. 3. The image forming apparatus according to claim 2, further comprising a warning unit that warns that the device is in a repaired state when it is determined that the maintenance is not performed. 4. The image forming apparatus according to claim 2, further comprising a warning unit that warns that maintenance is required when it is determined that maintenance is required. 5. The image forming apparatus according to claim 1, further comprising a pattern forming unit that forms a test pattern on the image carrier when determining whether maintenance of the cleaning unit is necessary. 6. An electrostatic latent image bearing member and a toner image developed on the electrostatic latent image bearing member are transferred onto a transfer material at a transfer portion which is the closest portion to the electrostatic latent image bearing member. Transfer device,
In an image forming apparatus having a fixing device for fixing toner on the transfer material, the toner on the electrostatic latent image carrier is transferred onto the transfer material, and the transfer material passes through the fixing device. Thus, when the toner is fixed and an image is formed, and then the toner on the electrostatic latent image carrier is transferred onto the transfer material again or a plurality of times to form an image, it is necessary to form the image at least once. Is an image forming apparatus characterized in that the electrostatic latent image carrier is idled for a long time. 7. The image forming apparatus according to claim 6, wherein the idle rotation is performed during post-rotation after a series of image formations at that time are all finished. 8. The image forming apparatus according to claim 6, wherein the idle rotation is performed for the longest time during image formation on the transfer material during multiple image formation. 9. An electrostatic latent image bearing member and a toner image developed on the electrostatic latent image bearing member are transferred onto a transfer material at a transfer portion which is the closest portion to the electrostatic latent image bearing member. Transfer device,
In an image forming apparatus having a fixing device for fixing toner on the transfer material, the toner on the electrostatic latent image carrier is transferred onto the transfer material, and the transfer material passes through the fixing device. Therefore, when the toner on the electrostatic latent image carrier is transferred onto the transfer material again or a plurality of times after the toner is fixed and the image is formed, at least once the single-sided image formation is performed. The image forming apparatus is characterized in that a large amount of toner is developed to develop the non-image area. 10. The image forming apparatus according to claim 9, wherein the developing operation on the non-image portion is performed during post-rotation after the series of image formations at that time are all completed. 11. The image forming apparatus according to claim 9, wherein the developing operation on the non-image portion is performed for the longest time when the image forming method on the transfer material is performed in multiple image formation. 12. The image forming apparatus according to claim 9, wherein the developing operation on the non-image portion is appropriately and appropriately performed according to the number of images to be formed, paper size, and image density. 13. A latent image forming means for forming a latent image on the surface of a moving image carrier, a developing means for developing the latent image formed by the latent image forming means, and abutting on the image carrier. An image forming apparatus comprising: a cleaning unit that cleans the surface of the image carrier; a reciprocating unit that reciprocates the cleaning unit in the longitudinal direction of the image carrier; and a control unit that controls the operation of the reciprocating unit. Is an image forming method characterized in that the reciprocating state of the cleaning means with respect to the image carrier by the reciprocating means does not change the sliding direction of the cleaning means with respect to the longitudinal direction during the formation of a latent image on the image carrier. apparatus. 14. The control unit according to claim 13, wherein the control unit forms a latent image on the image carrier in the reciprocating state of the cleaning unit by the reciprocating unit with respect to the image carrier, and develops the latent image in the longitudinal direction. An image forming apparatus characterized in that the sliding direction of the cleaning means with respect to is not changed. 15. The apparatus according to claim 13, wherein the apparatus has a transfer means for transferring the developed image on the surface of the image carrier to a transfer material, and the control means is in a state of reciprocation of the cleaning means by the reciprocating means with respect to the image carrier. An image forming apparatus characterized in that the sliding direction of the cleaning means with respect to the longitudinal direction is not changed during the period from the formation of the latent image on the image carrier to the development and transfer of the latent image. 16. Yellow, magenta, cyan or black is used as a color former, the image is formed on the image carrier by the color former, and after transfer to a transfer material, the color former on the image carrier is removed. In a multi-color image forming apparatus equipped with a cleaning device, a color developing agent of each color is formed on the image carrier in a single color by switching the drum rotation speed or the number of copies in addition to the desired image forming operation. Image forming apparatus.