JPH07121076A - Image forming device and cleaner therefor - Google Patents

Abstract

PURPOSE:To remove toner, oil, etc., stuck on an image carrier and a carry belt loaded in an image forming device equipped with a transfer-material carry belt arranged in the vicinity of at least one image-forming part. CONSTITUTION:A cleaning web 16 which runs is disposed in proper parts of the carry belt 8 which carries a transfer material, and a means for changing the pressure of a cleaning blade 18, which cleans the image carrier incorporated in the image forming part, on the image carrier or for applying a proper amount of toner to the edge of the blade is provided.

Description

Detailed Description of the Invention

[0001]

[Object of the Invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus utilizing an electrostatic transfer process, such as an electrostatic copying machine and a printer, and a cleaning apparatus therefor.

In the well-known image forming apparatus as described above, toner, fixing oil and other foreign matters are usually attached to an image carrier for carrying a toner image, a transfer belt for carrying a transfer material and guiding it to a transfer portion. Then, since it is unavoidable that this contaminates the transfer material, it is necessary to constantly clean such foreign matter. Such a need is remarkable in a color image forming apparatus in which a plurality of image forming units are provided in series and toner images of respective colors are sequentially formed, and when double-sided printing is performed.

Further, in this type of apparatus, since a fixing device having a heat source is usually arranged at a position after the completion of development, an image forming portion arranged close to the fixing device and a position far from the image forming portion. It is unavoidable that the temperature of the surrounding atmosphere is different from that of a certain image forming unit, and such a temperature difference affects the cleaning blade that cleans the image carrier disposed in each image forming unit, resulting in a difference in the cleaning function. This may lead to deterioration of image quality.

Further, in the case of each image forming section having the above-mentioned structure, it is necessary that a proper amount of toner as a lubricant always exists at the contact portion between the image bearing member and the blade edge of the cleaning blade contacting the image bearing member. However, when a large number of copies with low toner consumption are to be made, the amount of toner present at the blade edge portion becomes extremely small and the friction between the blade edge and the image carrier increases, which causes chattering. ,
There is a risk that the blade will be turned over and the cleaning function will be deteriorated, or in extreme cases, the cleaning will be impossible. This can also occur when the transfer belt as described above is cleaned by a cleaning blade.

FIG. 31 is a schematic side view of an image forming apparatus showing a typical example having a plurality of image forming sections. This will be briefly described. A pair of rollers 17a, 1
The conveyor belt 8 wound between 7b runs in the direction of arrow c by a drive source (not shown), and four image forming portions Pa, Pb, Pc and Pd are arranged on the upper surface of the belt 8 in the figure. There is. Since all the image forming units have the same configuration, only the image forming unit Pa will be outlined below.

In the image forming portion Pa, a cylindrical image carrier 1a which rotates in the direction of arrow A is arranged in the vicinity of the conveyor belt 8, and the surface photosensitive layer thereof is uniformly charged by the primary charger 15a. After this, the image signal 16a due to the black component of the document is added to this to form an electrostatic latent image.
Next, when this latent image reaches the position of the developing device 3a, black toner is supplied from this, and a black toner image is formed.

When this black toner image arrives at the transfer portion where the transfer charger 4a is arranged, a transfer material (not shown) is conveyed from the conveying path 12 to the transfer portion at the same timing, and together with this, the transfer charger 4a. A transfer bias is applied to the black toner image on the image carrier side, and the black toner image is transferred to the transfer material.

Thereafter, the residual toner remaining on the image carrier is removed by the cleaning device 5a, and the image carrier is ready for the next image forming step. On the other hand, the transfer material carrying the black toner image advances to the next image forming portion Pb.

The image forming portion Pb has the same structure as that of the image forming portion Pa, and in the same manner as the above case,
The latent image is formed, the magenta toner is supplied thereto, and the magenta toner image is transferred to the transfer material at this transfer position. Similarly, thereafter, after the cyan toner image and the yellow toner image are sequentially formed on the transfer material in the image forming portions Pc and Pd, the transfer material is usually a fixing device 7 having a pair of rollers heated to a predetermined temperature. The toner images of the respective colors are fixedly fixed on the transfer material and discharged to the outside of the apparatus through the pressure contact nip portion.

As described above, in the image forming apparatus as described above, it is necessary to sufficiently remove the transfer belt for transferring the transfer material and the toner and other foreign matter adhering irregularly on the surface of the image carrier in each image forming section. Can be said to be an essential requirement for obtaining good quality images.

The present invention has been made in view of the above circumstances, and the toner of the belt in the image forming apparatus including the belt for carrying and conveying the transfer material as described above,
Adhesion of oil or other foreign matter, change in the function of the cleaning blade with respect to the image carrier of the image forming apparatus, including individual image forming portions of such image forming apparatus, and further as a lubricant to the blade edge of the cleaning blade. It is an object of the present invention to provide a cleaning device capable of always performing stable and good cleaning by appropriately controlling conditions such as toner supply.

[0012]

[Constitution of the invention]

In order to achieve the above-mentioned object, the present invention provides an image forming apparatus in which at least one image forming section is provided in the vicinity of a conveyor belt which conveys a transfer material. A cleaning portion that comes into contact with the conveyor belt and cleans it by rubbing, and a portion that applies a cleaning aid to the conveyor belt on the upstream side of the cleaning portion when viewed in the traveling direction of the conveyor belt. In a cleaning device provided with a web, or an image forming device provided with at least one image forming unit in the vicinity of a conveyor belt that conveys a transfer material, an image viewed in the traveling direction of the conveyor belt. An image forming apparatus provided with an oil removing unit for removing oil adhering to the conveyor belt and the transfer material, on the upstream side of the forming unit. Alternatively, in an image forming apparatus in which the transfer material is sequentially fed to a plurality of image forming portions, and after the image formation, the transfer material is conveyed to a fixing device having a heat source, the image bearing member of each image forming portion is contacted. In an image forming apparatus provided with means for making the contact pressure of each cleaning blade in contact with each other uniform, or in an image forming apparatus having an image carrier and a cleaning blade in contact with the image carrier, the image is formed on the surface of the image carrier. Image forming apparatus or image carrier comprising a sensor for detecting the toner density of the toner image and a means for changing the contact condition of the cleaning blade with the image carrier according to the detected toner amount, and A cleaning blade in pressure contact with the input image signal, and means for detecting the input image signal and controlling the toner replenishment amount accordingly, the density calculated by the input image signal Developed this by forming a latent image of Patsuchi a further amount of toner developed Patsuchi detects, image forming apparatus and supplies this to the cleaning site by the toner supply amount by these two detection signals.

With this structure, the image forming apparatus using a single image carrier, a plurality of image forming units are arranged in a line, and the transfer material is sequentially conveyed to these image forming units by the conveyor belt. In such an apparatus, it is possible to effectively remove all unnecessary toner, oil, and other foreign matter attached to the image carrier and the conveyor belt.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS "FIG. 1" is a side view of an essential part showing an embodiment of the present invention, and is a drive section below a leftmost image forming section of an image forming apparatus as shown in "FIG. 31". The portion near the roller 17b is shown.

A pair of rollers 11 and 11 'are arranged below the conveyor belt 8 in the figure, and a cleaning web 16 made of non-woven fabric or the like is wound around the rollers 11, 11'. The conveyor belt 8 is continuously or intermittently wound up at a speed, and the surface of the conveyor belt 8 is rubbed and cleaned as described later.

A pair of cleaning rollers 14 and 15 and a pair of rollers consisting of a felt roller 12 and a sponge roller 13 are arranged on the portion of the web 16 stretched between the rollers 11 and 11 '. , 15 are
As shown in the figure, the belt 8 and the web 16 are sandwiched and brought into contact with each other. Further, the roller 13 is the driving side roller 1.
The belt 8 and the web 16 are clamped between 0 and the roller 1
Reference numeral 2 holds a web 16 between itself and a roller 13, and the roller 12 is impregnated with a cleaning aid such as silicone oil.

With this structure, the web 16 running in the direction of the white arrow shown in the figure and coming into contact with the felt roller 12 and containing the silicone oil forms the sponge roller 13.
The belt 8 is brought into contact with the belt to remove the toner adhering to the belt. When the belt 8 further advances and reaches the position of the cleaning roller pair 14 and 15, the web 16 removes the silicon oil remaining on the belt 8 at this position,
The belt 8 is in a clean state and reaches a position where the next image forming process is performed. As the silicone oil used as a cleaning aid, the felt roller 12 was impregnated with dimethyl silicone oil having a viscosity of 10,000 cst which is used for preventing offset of the fixing device.

Although the toner after transfer adheres strongly to the conveyor belt by electrostatic attraction, the cleaning function can be improved by using silicon oil as a cleaning aid as described above. On the other hand,
The belt may come into direct contact with the image bearing member at the image forming portion. At this time, if the silicone oil on the belt side adheres to the image bearing member, the image quality deteriorates. The silicone oil used to remove the above toner is then removed to a clean web, thus avoiding the above problems.

As the cleaning aid, in addition to silicone oil, water, a solvent such as alcohol, a fluorine-based lubricant, a silicon-based lubricant, a molybdenum disulfide-based lubricant, or the like can be appropriately used.

The feed amount of the web 16 does not have to be constant at all times, as mentioned above. In the worst case, when a conveyance failure occurs at the first position immediately before the image carrier after passing through a jam detection sensor (not shown), it is necessary to perform cleaning for a maximum two-color solid image while the belt makes one revolution. This is not necessary at the time of normal image formation, and may be appropriately set such that the feeding amount of the web is doubled when it is jammed or directly transferred to the belt.

FIG. 2 is a side view of a cleaning device according to another embodiment. In this device, a felt pad 17 impregnated with a cleaning aid is brought into contact with the conveyor belt 8 to face it. Felt pad 1 on the side
8 are arranged, and cleaning is performed by using both these pads using an auxiliary agent such as silicone oil.

Along with this, the felt pad 18
Is extended to the position of the cleaning roller 14 and one end of the pad 18 is arranged so as to contact the surface of the driving side roller 10. With this structure, the structure of the belt cleaning portion can be simplified and the driving roller can be cleaned at the same time.

FIG. 3 shows still another embodiment. In the illustrated apparatus, the web 16 suspended between the rollers 11 and 11 'is used for cleaning in the same manner as that shown in FIG. A container 2 held by the roller pair 14 and 15 of FIG.
3 is arranged so that the web 16 is pressed against the conveyor belt 8.

In the case of the illustrated apparatus, the container 23 is filled with carbon fluoride powder 19, and this is pressed from below by a piston 20 toward the web 16. Carbon fluoride powder is introduced into the web 16 through the porous member 21 in the opening of the container to clean the conveyor belt 8.

Generally, the particle size of carbon fluoride powder is 0.1.
It is as small as -10 μm and can easily pass through a thin porous member such as Pore Freon, felt, non-woven fabric or paper to reach the surface of the conveyor belt. With the above configuration, when the cleaning function needs to be changed, such as in the case of a normal cleaning operation and a special condition such as a jam, not only the web feed amount but also the piston pressure amount. The consumption efficiency of the cleaning aid can be improved by changing

As described above, in the case of directly applying silicone oil or the like as a cleaning aid for the cleaning of the conveyor belt, in the case of double-sided copying which has been frequently used recently, it is fixed as a release agent. The silicone oil applied to the heating roller of the device adheres to the transfer material and not only contaminates the next transfer material, but also it may transfer to the image carrier and adversely affect the subsequent image formation. Therefore, it is necessary to sufficiently remove the oil on the conveyor belt.

It is one of the objects of the present invention to avoid the deterioration of the image quality due to the contamination of the transfer material, the poor charging of the image carrier, the poor cleaning, etc. by removing the oil adhering to the conveyor belt in this way. An embodiment that conforms to will be described.

FIG. 4 shows an embodiment in which the present invention is applied to the image forming apparatus having the structure shown in FIG. 31. Corresponding parts are designated by the same reference numerals. ,
Descriptions thereof will be omitted unless necessary.

As shown in the figure, in this apparatus, the oil removing means 26 is arranged on the upstream side of the image forming portion Pa in the running direction of the belt 8, and the transfer material supplied from the conveying path 12 is provided. The surface of the belt is cleaned at a position before reaching the image forming portion Pa, and the transfer material is conveyed to the image forming portion without foreign matters such as oil adhering to the transfer material in the previous process. ing.

FIG. 5 is a side view schematically showing the structure of the oil removing means 26, and a pair of rollers 2 is provided near the belt 8.
A web 30 made of an appropriate material such as a non-woven fabric having the rollers 7 and 28 wound around and supported by the roller 28 is wound around the winding-side roller 27 at an appropriate speed by a drive source (not shown), and The web 30 is configured to slide on the surface of the transfer material traveling on the belt 8 by the pressing roller 29 located in the middle.

With this construction, the oil passes through the fixing portion once, and before the transfer material such as silicon oil adheres to the image forming portion again, the oil is placed at the position of the oil removing means 26. Since it is removed, good image forming work is always performed without causing the above-mentioned inconvenience.

FIG. 6 shows another embodiment, and the basic structure of the image forming apparatus itself is not particularly different from that shown in FIG.

In this apparatus, oil removing means 26a, 26b, 26c, and 26d are provided immediately before the transfer sites of the image forming sections Pa to Pd, respectively.
Then, these removing means 26a to 26d are turned on / off as the transfer material arrives at each image forming apparatus, and an image is formed according to the image forming mode. Transport path 12
The transfer material and the conveyor belt are operated by activating only the oil removing means disposed upstream of the predetermined image forming portion which is closest in distance to the above, and deactivating the oil removing means provided downstream thereof. Can be more efficiently rubbed and cleaned, and high-quality image formation can be more effectively performed.

FIG. 7 schematically shows the control mode of the oil removing means in the case of the above configuration, and the configuration of the oil removing means itself is the same as that shown in FIG. 5 and corresponds to it. The parts are shown with the same reference numerals.

In the case of this apparatus, the oil removing means 26 including the web 30 is built in a casing 31 which is rotatable by a pivot 34, and the casing 3 is a gear-shaped cam 3.
It is designed to rotate by 2.

The operation of the drive motor 36 and the clutch 37 is controlled by the control unit 35 in accordance with the image forming mode, and the clutch is provided for each oil removing means, one of which is shown in FIG. There is. This clutch rotates the gear 32 through the gear 33, and the cam action of the gear 32 swings the casing 31 to move the web 3
0 should be separated from the transfer material.

In an apparatus having a plurality of image forming sections as shown in FIG. 4 above, as shown in FIG.
Generally, the amount of silicone oil or the like deposited on the upstream side of the transfer material in the flow direction is large (N _a > N _b ≧ in the figure).
N _c ≧ N _d ), the oil removal means located closer to the upstream side,
It is necessary to strengthen the oil removal function.

Further, as shown in FIG. 10, it has been found that increasing the speed of the web increases the oil removing function, so that the oil removing means 26a to 26a are used.
The web transfer speeds v _{a to} v _d of the 6d web are shown in FIG.
Varied to Ozuru the oil adhesion amount of difference, as shown in _{(v a> v b ≧ v} c ≧ v d) efficient removal of oil is possible, also having a small web speed much of one turn by Since the web can last a long time, it is advantageous in terms of maintenance and cost.

Referring to FIG. 5, the drawing shows the oil removing means 26a on the most upstream side, but the other removing means have the same structure.

As shown in FIG. 8, the oil removing means 2
The shaft of the web winding roller 27a of 6a is projected to the outside, and the gear 42 attached to this is connected to the drive motor 40 via the gear 41a.

It is assumed that a gear 38a is arranged on the shaft of the drive motor 40, and a belt 39 arranged on the gear 38a is connected to a web winding roller below the removing means 26b (not shown).

In this manner, by appropriately changing the number of teeth of the intermediate gear 38a and the intermediate gears of the other oil removing means corresponding thereto, as shown in FIG. It is possible to change and adapt the oil removing function to the corresponding image forming unit.

Next, in the image forming apparatus having a plurality of image forming sections as described above, each image forming member is disposed in each image forming section and forms a toner image of each color. The function of the cleaning blade of the cleaning device for removing the generated residual toner will be described. In this type of image forming apparatus, as shown in FIG. 17, the fixing device is arranged at the last position of the transfer material conveying process.
Since the fixing device usually has a heat source, the temperature in the vicinity thereof, that is, in the vicinity of the image forming portion Pd is higher than the temperature in the far portion, that is, in the vicinity of the image forming portion Pa. Therefore, the cleaning blades 18a to 18d of the cleaning devices belonging to the respective image forming units also have a temperature T in the lower part of FIG.
It is inevitable that a temperature gradient will occur as indicated by a to Td. Incidentally, T _{F in} the figure shows the temperature of the fixing device.

However, the impact resilience of urethane rubber, which is most often used as a cleaning blade material, is shown in FIG.
As shown in the graph of "8", the temperature dependency is large, and if similar blades are used for all the image forming units, when the copying operation is continued for a long time, the image bearing member of the cleaning blade near the fixing device can be used. The contact pressure of the blade is strong and the blade of the distant portion becomes smaller, which causes a difference in the cleaning function. Also, in order to avoid such a situation, if the repulsion elastic modulus of the blade in the portion far from the fixing device is increased, that in the portion near the high temperature becomes extremely large and the blade edge wears, the photosensitive layer on the surface of the image carrier is damaged. However, problems such as excessive grinding occur.

That is, a uniform function can be obtained by preventing the variation of the contact pressure to the image carrier due to the temperature difference between the cleaning blades of each image forming section and the variation of the cleaning function due to the variation. This is one of the objects of the present invention.

An embodiment in which the present invention is applied to the image forming apparatus as shown in FIG. 31 will be described below. In FIG. 11, the image carriers 1a to 4d of the image forming units are respectively shown. Only the abutting cleaning blades 18a to 18d are shown.

Since the function of the cleaning blade abutting on the image carrier differs depending on the difference in the distance (referred to as the amount of penetration) between the position of the blade edge in the natural state and the position in contact with the image carrier. As shown in FIG. 11, the cleaning blade 1 provided in each image forming unit.
8a, 18b, 18c, and 18d, the set penetration amount of the blades 18a on the most upstream side when viewed in the traveling direction of the conveyor belt 8 from the set penetration amount δa of the downstream blades 18b, 18c,
It is configured such that it gradually becomes smaller as it goes to 18d.

As described above, when the cleaning blade is made of urethane rubber, the impact resilience thereof changes depending on the temperature as shown in FIG. 18, and the fixing device 7 as a heat source is used.
Since the contact pressure on the image bearing member increases with the position of the blade closer to, the blades 18a, 18b, 18
c, the amount of intrusion into the 18d image carrier .delta.a, [delta] b, the δc and [delta] d, as described above, and gradually smaller as leading to δd from .delta.a, intrusion amount each image forming during operation at a high temperature To be generally uniform in the area.

FIG. 12 shows the blade penetration amount δ and the contact pressure F on the image carrier in the cleaning device of the image forming section.
When the amount of penetration δa at the position of the image forming portion Pa (this temperature is Ta) is used as a reference, the temperatures Tb, Tc, and Td of the other blades 18b, 18c, and 18d are Since there is a tendency such as “Ta <Tb <Tc <Td”, the contact pressure to the image carrier is F in the figure.
A, Fb, Fc, and Fd may be changed to cause variations in the cleaning function, chattering, blade turning, and the like.

The penetration amount δa is set so that a certain value Fa equal to or higher than the minimum contact pressure F _{min that} can be cleaned is obtained at the blade 18a, and δb, δc, δd are set so that the contact pressure Fa at this time is obtained. By determining, the contact pressure of the blade of the cleaning device of each image forming unit can be made substantially uniform as a whole to perform cleaning. The temperatures Ta to Td, temperature gradients, etc. at the respective blade positions in the image forming apparatus are maintained substantially constant due to the configuration of the apparatus, the amount of heat generated by the fixing device, etc. Therefore, it is possible to set the amount of penetration as described above. It will be understandable immediately.

FIG. 13 shows another embodiment,
This drawing is an explanatory view showing only one image bearing member and a portion in the vicinity of the edge of the cleaning blade abutting on the image bearing member.

Amount of penetration of the edge of the cleaning blade δ
It is known that the contact pressure F becomes smaller as the set contact angle θ of the blade becomes smaller, when it is the same. In the figure, when θ> θ ′, the contact pressure Fθ> Fθ ′. Become.

Since there is the above relationship between the contact angle of the blade and the contact pressure, in the image forming apparatus as shown in FIG. 7, the blade located far from the fixing device as the heat source. The cleaning function of each blade can be uniformly maintained by gradually decreasing the set contact angle θ in accordance with the blades located closer to.

FIG. 14 is a graph for explaining that the above method is possible.
Is basically the same, and the description thereof is omitted.

With such a construction, not only the contact pressure of each blade can be maintained constant, but also the amount of penetration is constant, so that the blade wears and the image carrier wears.
It is also effective in preventing damage.

FIG. 15 shows another embodiment showing how to set the cleaning blade. The figure shows the image carrier 1.
And one of the cleaning blades 18 abutting this. An elastic backup member 21 such as phosphor bronze is disposed in contact with the cleaning blade 18 so that the free length 1 of the blade is variable.

In the case of such a configuration, when the amount of intrusion is constant, the contact pressure is reduced by changing the free length l to l '(l'> l) (Fl> Fl 'in the figure). A backup member is provided on each of the cleaning blades attached to the cleaning devices of the forming portions Pa or Pd, and the contact length of each blade can be made uniform by increasing the free length of each blade in this order. .

FIG. 16 shows that, when such a cleaning blade is used, at a certain free length la, the contact pressure between the blades becomes Fa to Fd due to the temperature change at each blade position.
Therefore, it is shown that the contact length of each blade can be made equal to Fa by changing the free length from la to ld.

With this configuration, each cleaning blade can maintain a uniform cleaning function at all times, and since the blades are in contact with the image bearing member with substantially the same amount of intrusion, the blade wear and the image bearing member can be prevented. It is effective in preventing damage.

Next, the cleaning means for removing the residual toner from the image carrier arranged in each image forming portion of the image forming apparatus as described above will be explained. in this case,
It is needless to say that the present invention can be applied not only to the above-described apparatus having a plurality of image forming units, but also to a well-known monochrome type image forming apparatus having a single image carrier.

FIG. 32 is a schematic side sectional view showing a typical example of such a cleaning device, in which the cleaning device 54 is arranged in proximity to the image carrier 50 which rotates in the direction of arrow A. A cleaning blade 55 is attached to the cleaning device 54, and a free edge of the cleaning blade 55 contacts the surface of the image carrier 50 to scrape off and remove residual toner not transferred to a transfer material at a transfer portion (not shown). To do.

The toner scraped off is conveyed by the conveying screw 5.
It is assumed that the sheet is sequentially conveyed to the outside by means of 8. Reference numeral 57 in the figure denotes a cleaning roller for removing paper dust, nitrogen oxides, and other foreign matter that are scattered on the surface of the image carrier.

In the cleaning device having such a structure,
Since the cleaning blades are usually arranged in the counter direction, the friction with the image bearing member is large, so that the blade 55 contacts the image bearing member between the blade edge 55a and the surface of the image bearing member. It is necessary that a proper amount of toner is always present and the lubricant acts on the toner to smoothly move the blade edge. However, when a large amount of toner is used with a small amount of toner, the amount of residual toner is small, so the amount of toner that reaches the blade edge is small, and the amount of toner that lubricates the edge portion is also small. The friction between them becomes large, and problems such as chattering and blade flipping occur.

In order to deal with such a situation, the amount of toner existing on the surface of the image bearing member is detected, and the contact pressure of the cleaning blade to the image bearing member is changed according to the value to maintain the toner removing function. At the same time, it is an object of the present invention to prevent abrasion of the blade edge, damage to the image bearing member, and the like.

FIG. 19 is a schematic side view of the image forming apparatus showing the embodiment of the present invention. The surface of the cylindrical image carrier 50 that rotates in the direction of arrow A is uniformly charged by the primary charger 51, and an image signal 52 is applied to this charged surface to form an electrostatic latent image.

When this latent image reaches a developing portion where the image carrier 50 and the developing device 53 (only the developing sleeve is shown in the drawing) face each other, the latent image is formed by the toner supplied from the developing device. When the toner image is visualized and reaches the transfer portion where the transfer charger T is located, the transfer material P is supplied to the transfer portion at the same timing and applied to the transfer charger. It is assumed that the toner image on the image carrier side is transferred to the transfer material by the action of the transfer bias, and the transfer material is conveyed to a fixing portion (not shown).

The toner that has not transferred to the transfer material during the transfer progresses to the image carrier while traveling to the position of the cleaning device 54, and is removed by the cleaning blade 55 so that the image carrier is ready for the next image forming step. It is ready to enter.

In such an image forming apparatus, in the illustrated case, a sensor 100 for detecting the image density is arranged at the position where the toner image is formed, and the cleaning blade 55 is held by a holding member 55a. In addition, the holding member 55a can be swung in the X direction in the drawing so that the pressure contact force of the cleaning blade 55 with respect to the image carrier can be changed.

Then, as shown in FIG.
When the position detected by the sensor 100 reaches the cleaning blade 55, the holding member 55a is displaced so that the blade 55 has a preset linear pressure, and cleaning is performed with a linear pressure suitable for the image density. .

FIG. 20 shows an example of the relationship between the amount of toner on the image carrier and the linear pressure of the cleaning blade.
Change the linear pressure according to the toner amount as shown by the solid line in the range of the minimum linear pressure that can remove the fog and the name on the image carrier and up to the maximum toner amount as in the case of solid black images. Just do it.

With such a structure, as in the conventional case,
The cleaning blade does not always have to be pressed against the image carrier with maximum pressure so that it can be removed even when the expected maximum amount of residual toner arrives, and therefore damage to the photosensitive layer of the image carrier or Without causing excessive wear,
Stable cleaning can be performed over a long period of time.

FIG. 21 is a schematic side view of an image forming apparatus showing another embodiment of the present invention, in which parts corresponding to those in the above embodiment are designated by the same reference numerals,
A description thereof will be omitted.

In this apparatus, the cleaning blade 55 is arranged so as to change its position and direction in the Y ₁ and Y ₂ directions in the drawing to change the contact angle of the cleaning blade with respect to the image carrier. When it is detected, the contact angle is changed by tilting in the Y ₁ direction and in the Y ₂ direction when it is determined that the amount is small.

FIG. 22 shows the relationship between the amount of toner and the contact angle of the breaker in the same manner as in the case of FIG. 20, in which the contact angle can be adjusted according to the solid line in the figure according to the amount of toner. Good.

In the above apparatus, when there is no residual toner, such as continuous copying of images having a low image density, or when idling is continued, a small amount of toner is left in the non-image area of the image carrier. By maintaining latent image formation and development, the cleaning property is maintained.
It is possible to extend the life of the cleaning blade and the image bearing member.

Next, another means for cleaning the surface of a single image carrier as described above will be described. It is assumed that the cleaning device itself has the structure shown in FIG.

As described above, it is necessary to always provide an appropriate amount of toner between the blade edge of the cleaning blade and the surface of the image carrier on which the cleaning blade abuts. As a means for this, an input image signal from the original document is used. It has already been proposed that the toner consumption amount is estimated by adding up and the toner consumption amount is supplied to the non-image area between images in the form of development. As a result, the toner amount fluctuates due to factors such as the above, and the toner amount at the relevant portion largely deviates from the set value.

To cope with such a situation, it is an object of the present invention to reliably supply an amount of toner suitable for the document density to the cleaning blade edge portion to always perform stable cleaning. Hereinafter, such an embodiment will be described.

FIG. 23 is a schematic explanatory view of an image forming apparatus schematically showing an embodiment of the present invention. The surface of a cylindrical image carrier 614 rotating and running in the direction of arrow A is uniformly distributed by a primary charger 616. An electrostatic latent image is formed on the charged surface by applying an image signal to the charged surface in a manner described later. When the latent image reaches the developing portion where the developing device 615 is located, toner is supplied from the developing device to form a toner image, and the image carrier 614 further rotates to transfer the toner image to the transfer charging device 6.
When reaching the transfer portion where 17 exists, a transfer bias is applied to the transfer charger, and the toner image on the image carrier side is transferred to the transfer material P by this time by the action of the electric field formed. Transfer. After that, the residual toner that has not transferred to the transfer material is removed by the cleaning device 618, and the residual charge is removed by the pre-electrification lamp 619, so that the surface of the image carrier is ready for the next image forming step.

Next, the formation of the electrostatic latent image and toner image of the above apparatus will be described. An original is read by the CCD 601, the input image signal is A / D converted 603, γ converted 605, D / A converted 609, and a triangular wave. With the triangular wave generated by the generation circuit 610, a PWM signal is generated by the comparator 611, and an electrostatic latent image is formed on the charged surface of the image carrier 614 via the scanning means 613. A / D at the same time
The density level of the converted input image signal is counted by the video counter 604 for each pixel,
The toner replenishing drive circuit 607 is controlled by the integrated value obtained by 606 to determine the drive time of the toner replenishing device 608, and the supply of toner to the developing device 615 is adjusted to match the image density.

In such an image forming apparatus, the A / D
The converted input image signal is counted for each pixel by the video counter 4, the density level corresponding to one page of the original is integrated, and then the CPU carries out image carrying of the patch of the density determined by conversion by the table prepared in advance. It shall be output to the body. It is appropriate to set the output timing to a non-image area between paper sheets between one image signal and an image signal adjacent thereto. Further, it is suitable that the size of the patch is approximately the same length in the longitudinal direction of the cleaning blade and about 0.5 to 30 mm in the running direction of the image carrier. The patch output does not necessarily have to be carried out for all the paper intervals, and it is of course possible to output the patch for every several paper intervals.

FIG. 24 shows an example of the threshold table. The figure shows the relationship between the integrated value of the density level per page and the patch output signal. In the case of a full solid black image,
Since a large amount of toner is supplied to the blade edge, the patch output is set to zero (point b in the figure), and when there is a white image on the entire surface (point a in the figure), there is no toner reaching the blade edge. Is set so that the patch output becomes maximum.

Further, as shown in FIG. 23, the patch density output to the image carrier is detected by the sensor 625, and the prepared patch output level, patch density, and patch are prepared as shown in FIG. 25. The developer concentration is predicted from a table showing the relationship between the concentration and the developer concentration, and the toner amount is controlled by operating so as to superimpose it on the toner replenishment control means. With such a structure, an image with more stable density was obtained.

For example, as shown in FIG. 25, when the calculated patch level is 120, the read density is 1.0.
If so, the straight line a in FIG.
%), Toner is not replenished, but when the consumption amount is large compared to the count number and the toner concentration is low, the result is as shown by the straight line b in the figure, and even at the same level 120, the developer concentration is -2%. Necessary to replenish toner.

The toner supply amount may be determined by preparing a table as shown in FIG. 26 for setting the relationship between the toner density and the supply charge. In the above case, the toner replenishment amount when the read developer concentration is -2% is about 0.25 gr.
/ Sec.

As described above, the toner replenishment amount is determined by the input image signal, and the density of the patch formed on the image carrier is referred to, so that the developer density can be controlled more stably.

FIG. 27 and FIG. 28 show another embodiment. As shown in FIG. 27, the density level in the width direction of the image area and the longitudinal direction of the cleaning blade, that is, the toner amount. When the histogram of the above is created, chattering of the blade edge is likely to occur in the portion where this value is low. Therefore, as shown in FIG. 28, a table obtained by inversely converting the histogram is constructed, and the output in the longitudinal direction of the blade is accordingly formed. Set the patch.

With this arrangement, the toner can be supplied as evenly as possible in the longitudinal direction of the blade edge, and stable cleaning can be performed.

FIG. 30 shows still another embodiment. As is well known, the length of the cleaning blade is usually longer than the image area width on the image carrier side, and there is no toner supply to the blade edge portion that abuts the non-image area. Moreover, the portions near both ends of the blade have a weaker effect against edge reversal than the central portion, so chattering and blade curling are more likely to occur.

For this reason, as shown in the same figure, a cleaning function is provided by constantly outputting an appropriate amount of patch to the portion corresponding to the blade edge outside the image area so that the toner can be constantly supplied to the blade edge portion. Can be further stabilized. Further, in general, in this type of image forming apparatus, the length of the cleaning blade is set so as to match the maximum transferable width. Therefore, even when a small-width original is given, the above-mentioned configuration is adopted. As a result, good cleaning can always be performed.

[0091]

As described above, according to the present invention, the residual toner on the image bearing member of the image forming apparatus and the conveying belt arranged in the vicinity of the image forming apparatus having a plurality of image forming units arranged in a row are used. In the cleaning means for removing toner, oil, etc. attached to the conveyor belt so that the transfer material is sequentially supplied, the toner adhered to the conveyor belt is sufficiently removed by using a cleaning aid such as silicone oil, Furthermore, this auxiliary agent, oil used for the fixing device, etc. are reliably removed at the image forming position, and the characteristics change due to the temperature difference of the cleaning blade used for removing residual toner in each image forming section is also supported. As a result, the cleaning function of each image forming unit is made uniform, and further, cleaning in one image forming unit is performed. It is possible to also maintain optimal contact state relative to the image bearing member blade, there is a remarkable effect in obtaining an image of usage chamber.

[Brief description of drawings]

1 to

FIG. 3 is a side view showing an embodiment of a cleaning device for cleaning a conveyor belt.

FIG. 4 is a side view of an image forming apparatus showing another embodiment of the same.

FIG. 5 is a side sectional view showing a configuration of oil removing means of the same apparatus.

FIG. 6 is a side view of an image forming apparatus showing another embodiment of the same.

FIG. 7 is an explanatory view showing a control system of an oil removing means of the same apparatus.

FIG. 8 is an explanatory view showing a configuration in which the oil removing function is changed when a plurality of oil removing means are provided.

FIG. 9 is a graph showing changes in the amount of oil attached to each of a plurality of image forming units.

FIG. 10 is a graph showing the relationship between the speed of the oil removing web and the cleaning effect.

FIG. 11 is an explanatory view showing only an aspect of contact between an image bearing member and a cleaning blade in an apparatus having a plurality of image forming units according to an embodiment of the present invention.

FIG. 12 is a graph showing the relationship between the amount of penetration of the cleaning blade into the image carrier and the contact pressure.

FIG. 13 is a side view of a main portion showing a cleaning portion portion according to another embodiment.

FIG. 14 is a graph showing the relationship between the contact angle of the cleaning blade with the image carrier and the contact pressure.

FIG. 15 is a side view of a main part of a cleaning portion showing still another embodiment.

FIG. 16 is a graph showing the relationship between the free length of the cleaning blade and the contact pressure.

FIG. 17 is a side view showing an aspect of a temperature piece of each image forming unit in an image forming apparatus having a plurality of image forming units.

FIG. 18 is a graph showing temperature characteristics of impact resilience of a urethane rubber blade.

FIG. 19 is a schematic side view showing an embodiment when the present invention is applied to an image forming apparatus having a single image carrier.

FIG. 20 is a graph showing the same effect.

FIG. 21 is a schematic side view showing another embodiment.

FIG. 22 is a graph showing the same effect as above.

FIG. 23 is a schematic view for explaining the operation of the image forming apparatus showing another embodiment of the present invention.

FIG. 24 is a graph showing an example of a threshold table used in the above.

FIG. 25 and

FIG. 26 is a table that determines how to set the toner supply amount of the same as above.

FIG. 27 is an example of a histogram showing the toner concentration distribution in the longitudinal direction of the cleaning blade.

FIG. 28: Density level distribution of output patch obtained by reversing the histogram of the above

FIG. 29 is a diagram for explaining a method of capturing the output patch of the same as above.

FIG. 30 is a graph showing the case where the density level of the output patch is also present outside the longitudinal image area of the cleaning blade.

FIG. 31 is a schematic side view showing the configuration of an image forming apparatus including a plurality of image forming units.

FIG. 32 is a side sectional view showing a configuration of a cleaning device arranged on a single image carrier.

[Explanation of symbols]

1a to 1d Image carrier 3a Developing device 4a to 4d Transfer charging device 5a Cleaning device 7 Fixing device 8 Conveying belt 11, 11 'Cleaning web winding roller 12 Cleaning auxiliary agent applying roller 15a Primary charging device 16,30 Cleaning web 16a image Signal 17 Cleaning aid application pad 17a, 17b Belt winding roller 18a to 18d Cleaning blade 20 Piston 21 Porous 23 Container 26, 26a to 26d Oil removing means 50 Image carrier 51 Primary charger 53 Developer 54 Cleaning device 55 Cleaning Blade 56 CPU 100 Sensor 601 CCD 603 A / D conversion circuit 604 Video counter 606 CPU 608 Toner replenishing device 609 D / A conversion circuit 613 Scanning means 614 Image bearing Body 615 developing device 616 the primary charger 618 cleaning device 625 sensor

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[Procedure amendment]

[Submission date] September 1, 1994

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

FIG. 28

[Figure 7]

[Figure 6]

[Figure 8]

[Figure 9]

[Figure 10]

FIG. 11

[Fig. 12]

[Fig. 13]

FIG. 15

FIG. 24

FIG. 14

FIG. 16

FIG. 18

FIG. 17

FIG. 19

FIG. 20

FIG. 21

FIG. 26

FIG. 27

FIG. 30

FIG. 22

FIG. 23

FIG. 25

FIG. 29

FIG. 32

FIG. 31

Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location 6605-2H 322 (72) Inventor Takao Ogata 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. ( 72) Inventor Yoshihiro Takada 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Ikuo Kuribayashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Koji Amamiya 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (15)

[Claims] 1. An image forming apparatus in which at least one image forming unit is disposed in the vicinity of a conveyor belt that conveys a transfer material, and a cleaning portion that abuts on the conveyor belt and cleans it by rubbing. A cleaning device provided with a cleaning web having a portion for applying a cleaning aid to the conveyor belt on the upstream side of the cleaning portion when viewed in the traveling direction of the conveyor belt. 2. The cleaning device according to claim 1, wherein the means for applying the cleaning aid can change the amount of the aid. 3. The "claim 1" or "claim 2" wherein the cleaning aid is a material selected from water, alcohol, a fluorine-based lubricant, a silicon-based lubricant, and a molybdenum disulfide-based lubricant. The cleaning device described. 4. An image forming apparatus comprising at least one image forming section arranged in the vicinity of a conveyor belt for conveying a transfer material, in an upstream side of the image forming section when viewed in the traveling direction of the conveyor belt. An image forming apparatus provided with an oil removing unit for removing oil adhering to the conveyor belt and the transfer material. 5. An image forming apparatus comprising a plurality of image forming units arranged in the vicinity of a conveyor belt for conveying a transfer material, wherein the conveyor belt is upstream of each image forming unit when viewed in the traveling direction of the conveyor belt. In order to remove the oil adhering to the transfer material, an oil removing means is provided respectively, and the oil removing function of each oil removing means is changed according to the distance from the portion supplying the transfer material to the conveyor belt. Image forming apparatus. 6. The image forming apparatus according to claim 4, wherein the oil removing means has a web that is slidably displaced on the conveyor belt. 7. The image forming apparatus according to claim 5, wherein the oil removing means is a web that slides on the conveyor belt, and the means that changes the oil removing function is a means that changes the rubbing speed of the web. 8. An image carrier for each image forming section in an image forming apparatus, wherein the transfer material is sequentially fed to a plurality of image forming sections, and after the image formation, the transfer material is conveyed to a fixing device having a heat source. An image forming apparatus comprising means for equalizing the contact pressure of each cleaning blade that contacts the body. 9. The image forming apparatus according to claim 8, wherein the means for making the contact pressure uniform is a means for sequentially changing the amount of the cleaning blade entering the image carrier. 10. The image forming apparatus according to claim 8, wherein the means for making the contact pressure uniform is means for sequentially changing the contact angle of the cleaning blade with the image carrier. 11. The image according to claim 8, wherein the means for making the contact pressure uniform is a means for changing the position of the backup member arranged in contact with the cleaning blade to change the free length of the cleaning blade. Forming equipment. 12. An image forming apparatus comprising an image carrier and a cleaning blade in contact therewith, a sensor for detecting a toner density of a toner image formed on the surface of the image carrier, and a sensor for detecting the toner amount according to the detected toner amount. An image forming apparatus including means for changing the contact condition of the cleaning blade with the image carrier. 13. The image forming apparatus according to claim 12, wherein the means for changing the contact condition is means for changing the contact pressure of the cleaning blade on the image carrier. 14. The image forming apparatus according to claim 12, wherein the means for changing the contact condition is means for changing the contact angle of the cleaning blade with the image carrier. 15. An image carrier, a cleaning blade in pressure contact with the image carrier, and means for detecting an input image signal and controlling a toner replenishment amount in accordance with the image signal, which are calculated by the input image signal. An image forming apparatus which forms a latent image of a patch having a density, develops the latent image, detects the toner amount of the developed patch, supplies a toner replenishment amount based on both detection signals, and supplies the toner to a cleaning portion.