JP2002202667A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the performance of a cleaning member by a simple method in a cleaning device in which toner remaining on an intermediate transfer body after transferring the toner image to recording paper from the surface of the intermediate transfer body is recovered by utilizing the adhesive strength of the member. SOLUTION: The image transferred to the recording paper is formed by forming an electrostatic latent image on a photoreceptor drum 4 and transferring the toner to the latent image from a developing device 5. After the image is transferred to the intermediate transfer body 1, it is heated and melted, and made to press-contact with the recording paper by a heating roller 12 and a pressure roller 17. In addition to the image transferred to the recording paper, the toner image for maintenance of a cleaning roller is formed on the drum 4 and transferred to the transfer body 1, and then stuck to the surface of the heated cleaning roller 7 without being transferred to the recording paper. Thus, even when much paper powder or the like adheres to the surface of the cleaning roller, the toner layer having stickiness when it is heated is formed on the surface thereof, so that the adhesion of the cleaning roller is recovered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a copying machine,
More specifically, the present invention relates to an image forming apparatus such as a printer and a facsimile, and more specifically, a primary transfer of a toner image formed on an image carrier onto an intermediate transfer body, and then a secondary transfer onto a recording medium by heating and pressing. And an image forming apparatus for performing fixing.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electrophotographic system or an electrostatic recording system, an electrostatic latent image formed on an image carrier is developed by attaching toner, and then the toner image is transferred to a recording medium. Is fixed by heat and pressure. As a method of transferring and fixing the toner image, a method is conceivable in which the toner image is temporarily transferred to an intermediate transfer member, and then the heated and melted toner image is pressed against a recording medium to simultaneously perform the transfer and the fixing. . This method is particularly suitable for a color image forming apparatus, in which primary transfer of a toner image is performed under stable conditions, and secondary transfer and fixing of a plurality of color toner images superimposed on an intermediate transfer member are collectively performed. Simultaneously, high image quality can be obtained.

In general, a method of contacting a blade or a brush-like member made of an elastic material is used for cleaning toner remaining on an image carrier or an intermediate transfer member after a toner image is electrostatically fixed. However, when the toner is heated and melted on the intermediate transfer body, the adhesive force between the toner and the intermediate transfer body is increased, and the above-described cleaning unit is required to effectively remove the residual toner. Is difficult.
For this reason, as a technique for cleaning the intermediate transfer member after transferring the heat-fused toner image on the intermediate transfer member, JP-A-63-189878, JP-B-4-31394, and JP-B-4-4-1394. There is one disclosed in Japanese Patent No. 45829.

All of the cleaning techniques described in the above publications have a configuration in which a heated cleaning roller is pressed against the surface of an intermediate transfer member to adhere and remove residual toner having softened and increased adhesion. . In particular, the apparatus described in Japanese Patent Publication No. 4-31394 has a layer of the same resin as the toner on the peripheral surface of the cleaning roller, and this resin layer is heated to have a large adhesive force.
Therefore, residual toner on the intermediate transfer member is efficiently removed, and good cleaning is performed.

[0005]

However, the apparatus having the resin layer on the peripheral surface of the cleaning roller as described above has the following problems. Since the intermediate transfer member comes into contact with the sheet, paper dust of the recording sheet adheres to the surface of the intermediate transfer member. The paper dust adhering to the surface of the intermediate transfer member moves to the cleaning position with the rotation of the intermediate transfer member, and adheres to the surface by the adhesive force of the cleaning member. The surface of the cleaning roller is made of a resin, and generates an adhesive force by heating the resin. However, since the paper dust does not have adhesiveness, if the amount of paper dust attached to the surface of the cleaning roller increases, the adhesiveness of the cleaning roller surface decreases.

In a state where paper powder does not adhere to the surface of the cleaning roller, the heated cleaning roller and the toner to be cleaned adhered on the intermediate transfer member exhibit adhesiveness to each other, so that the cleaning performance is also improved. However, if the toner on the intermediate transfer member is cleaned while the paper dust is adhered, the adhesion of the cleaning roller and the toner is reduced because the surface of the cleaning roller does not have sufficient adhesiveness. Cleaning failure occurs.

The results of an experiment conducted to verify this problem are shown below. Heat and melt the toner image on the intermediate transfer member,
In an image forming apparatus that simultaneously performs transfer and fixing to a recording medium, 100 sheets of typical paper (plain paper or lightly coated paper) used in an office were sent to a transfer-fixing unit and brought into contact with an intermediate transfer member. Thereafter, the intermediate transfer member is cleaned by a cleaning roller. FIG. 10 shows the result of investigating the degree to which the cleaning performance of the cleaning roller is reduced thereafter. In FIG. 10, a cleaning test is performed on several types of images to be cleaned in which the density and shape are changed, and a state in which cleaning is completely performed on each image is classified as grade 0, and a state in which cleaning is not performed at all is classified as grade 4. A numerical value between these values is defined as a cleaning grade value. This experiment shows that the cleaning performance is reduced by passing 100 sheets, and the required performance is not satisfied depending on the type of recording paper.

Further, the amount of paper dust adhering to the surface of the cleaning member after performing the above-described experiment was measured by the light reflectance of the surface of the cleaning member, and the result was replaced with a grade value, and an image forming apparatus using the cleaning member was used. FIG. 11 shows the relationship with the cleaning grade. According to this experimental result,
There is a correlation between the amount of paper dust adhering to the cleaning roller surface and the cleaning grade, and it can be seen that the adhering paper dust reduces the cleaning performance.

As means for solving this problem, Japanese Patent Application Laid-Open
Japanese Patent Application Laid-Open No. 61-256372 discloses an apparatus provided with a means for applying a new adhesive material layer to a cleaning roller to which paper powder or the like has adhered. However, this method has the drawback that the cost for updating the apparatus is high, and that a large space is required in the apparatus, so that the image forming apparatus is large and expensive.

The present invention has been made in view of such a problem, and an object of the present invention is to transfer a toner image from a surface of an intermediate transfer member to a recording sheet and then leave the toner image on the intermediate transfer member. An object of the present invention is to maintain the performance of the cleaning member by a simple method in a cleaning device that collects the used toner using the adhesive force of the member.

[0011]

In order to solve the above-mentioned problems, the invention according to claim 1 is directed to an image carrier in which a latent image due to a difference in electrostatic potential is formed on a surface, and an image carrier having a latent image formed thereon. A developing unit that visualizes the electrostatic latent image by attaching toner to the intermediate latent image, and an intermediate surface that has an endless peripheral surface that moves around and on which the toner image formed on the image carrier is primarily transferred. A transfer unit, a heating unit that heats and melts the toner image on the intermediate transfer body, a transfer fixing unit that presses the melted toner image onto a recording medium, and simultaneously performs secondary transfer and fixing, and heats the adhesive. A cleaning member that has a resin layer having an endless peripheral surface, is pressed against the intermediate transfer body after the secondary transfer, and adheres and removes residual toner to the resin layer. In addition to the toner image transferred to the recording medium on the image carrier, After forming a maintenance toner image that is not transferred to the recording medium and transferring the maintenance toner image onto the intermediate transfer member, the toner image is maintained over the entire circumference of the cleaning member in a range equal to or greater than the full width of the recording medium used. An object of the present invention is to provide an image forming apparatus which is set so as to attach a management toner image.

In the above image forming apparatus, a maintenance toner image is formed on an intermediate transfer member, and this toner image is not transferred to a recording medium, but is brought into contact with a cleaning member.
Attach it to the cleaning member to which the paper dust has adhered. Therefore, a new toner layer is formed so as to cover the surface of the cleaning member that has deteriorated due to the adhesion of the paper powder, and the adhesive strength is restored, and the cleaning performance is maintained.

The area where the maintenance toner image is formed is equal to or longer than the peripheral length of the cleaning member having the endless peripheral surface. Thus, toner can be supplied to the entire surface of the cleaning member, and uniform cleaning performance can be maintained.

The timing and frequency of forming the toner image may be arbitrarily set, and may be set for each prescribed sheet passing time or sheet number. If a toner image for maintenance is formed when the power of the image forming apparatus is turned on, the maintenance of the cleaning member can be performed without lowering the productivity of image output.

Further, when the user notices the deterioration of the image quality due to the deterioration of the cleaning ability, a signal input by the user (for example, a signal from a cleaning instruction switch, a signal from a personal computer connected via a network, etc.).
By creating a maintenance toner image and supplying it to the cleaning member, it is possible to maintain the cleaning performance in accordance with various paper usage conditions and the like.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the maintenance management toner image transferred onto the intermediate transfer member particularly corresponds to the vicinity of both side edges in the width direction of the recording medium. The toner amount in the range is set so as to be larger than the toner amount in the other ranges.

Since a large amount of paper dust attached to the cleaning member is generated from the edge of the recording paper, the cleaning member surface corresponding to the edge of the recording paper has a greater amount of dust than the other surface. The paper dust adheres, and the cleaning performance of that portion is reduced. On the other hand, when the toner supply amount is increased, the degree of recovery of the cleaning performance is increased. The supply of the toner is reduced to a relatively small portion of. As a result, it is possible to recover the uniform cleaning performance while suppressing the toner consumption as a whole.

According to a third aspect of the present invention, in the image forming apparatus of the second aspect, recording medium detecting means for detecting, for each size, the number of recording media onto which the toner image on the intermediate transfer member has been transferred is provided. The range in which the toner amount of the maintenance toner image is increased corresponds to the vicinity of both side edges of the size of the recording medium in which the transfer and fixing of the predetermined number or more are detected. Range.

In such an image forming apparatus, even when sheets of different sizes are appropriately used after the last time when the maintenance toner image is formed, the portion where a large amount of paper dust is accumulated can be precisely formed. The toner can be supplied, and the amount of toner consumption as a whole can be suppressed.

According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, a part of the maintenance toner image forms an image for adjusting image density or forms a toner image. This is an image for adjusting the position.

In general, a technique is known in which a reference patch for density adjustment (for example, a halftone image having a predetermined area ratio) is formed on an image carrier, and the developed density is measured to adjust the density. . In particular, in a device for forming a color image, it is necessary to strictly adjust the density of the intermediate color, and reference patches are frequently created. In an apparatus for superposing toner images of a plurality of colors on the intermediate transfer member, a toner image for positioning is formed in order to adjust a position where the toner image is formed.
After these toner images are transferred to the intermediate transfer member, they are not transferred to the recording paper but are removed by the cleaning device. Therefore, these toner images can be used as all or a part of the maintenance toner image supplied to the surface of the cleaning roller. In addition, by using the toner in this way, it is possible to reduce the amount of toner used and to suppress a decrease in the efficiency of image formation.

According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the maintenance / management toner image is formed by being divided into a plurality on the intermediate transfer member, and the cleaning member is provided. When it is attached to the peripheral surface of the cleaning member, it is formed such that it adheres without a gap over the entire circumference of the cleaning member having the endless peripheral surface.

The maintenance toner image to be supplied to the cleaning member does not need to be formed as one continuous toner image on the intermediate transfer member, but may be a plurality of divided toner images. However, if there is a portion where the toner is not supplied on the surface of the cleaning member having the endless peripheral surface,
Since the cleaning performance of that part is not restored,
It is necessary to supply the toner to the entire peripheral surface of the cleaning member. Therefore, the total length of the plurality of maintenance toner images in the moving direction is formed to be longer than the peripheral length of the cleaning member having the endless peripheral surface, and the position at which the divided toner images are formed and the cleaning member The circumference must be regular.

When a plurality of divided maintenance toner images are used as described above, since each of the image lengths may be short, the image is formed as an inter-image between the image to be transferred to the recording medium and the next image. It becomes possible. This makes it possible to form a toner image for recovering the cleaning performance and supply the toner image to the cleaning member at the same time as the image output (paper passing), thereby reducing the influence on the image forming speed per unit time. can do.

According to a sixth aspect of the present invention, in the image forming apparatus of the first to fifth aspects, the developing means includes a plurality of developing devices each containing a toner of a different color. The toner image for maintenance is provided with a toner sensor for detecting the amount of toner contained in each of the developing devices. It is assumed that it is formed by a plurality of developing devices sequentially selected from those.

Generally, in an image forming apparatus using toners of a plurality of colors, the amount of toner used differs between the toners of the respective colors. Therefore, by forming the maintenance toner image with the toner having a large remaining amount, the usage amount of the toner of each color can be averaged, and the toner replenishment frequency of the user can be reduced.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the invention according to the present application will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. This image forming apparatus includes an endless belt-shaped intermediate transfer body 1 whose peripheral surface is rotatably supported. A yellow, magenta, cyan, and black toner image is formed at a position facing the intermediate transfer body 1. Four image forming units 2a, 2b, 2c, and 2d to be formed are provided.

Each of the image forming units 2a, 2b, 2c, 2d has a photosensitive drum 4a, 4b, 4c, 4d on the surface of which an electrostatic latent image is formed.
Around each photosensitive drum, a charging device 3a that charges the surface of the photosensitive drum almost uniformly,
3b, 3c, 3d, an optical scanning device 10 for scanning a surface of each photosensitive drum with a laser beam to write an electrostatic latent image, and yellow, magenta, and yellow for each latent image formed on the photosensitive drum.
Developing devices 5a, 5b, 5c, 5d for transferring cyan or black toner, respectively, to form toner images, and primary transfer rollers 6a for primarily transferring the toner images on the respective photosensitive drums onto the intermediate transfer body 1; 6b, 6c, and 6d.

Inside the intermediate transfer member 1, a driving roller 11, a heating roller 12, a peeling roller 13, and an opposing roller 1
The intermediate transfer member 1 is stretched around these rollers and driven to rotate. On the upstream side of the heating roller 12 in the circumferential direction of the intermediate transfer body 1, a heating plate 16 is provided along the inside of the intermediate transfer body 1. The toner image on the transfer body 1 is heated.

Further, at a position facing the heating roller 12 with the intermediate transfer member 1 interposed therebetween, a pressure roller 17 for sandwiching and heating and pressing the recording paper is provided.
Is fed between the intermediate transfer body 1 and the pressure roller 17 by the paper feeding device 20, and the secondary transfer and fixing of the toner image are performed simultaneously. Further, a cooling device 18 for cooling the recording paper after the transfer and fixing is provided downstream of the position where the heating roller 17 is provided.

A cleaning roller 7 having a built-in heating device is disposed at a position facing the opposing roller 14 with the intermediate transfer member 1 interposed therebetween. The toner remaining on the surface of the intermediate transfer member 1 is heated. The toner adheres to the cleaning roller 7 and is removed. The cleaning roller 7 is retracted to a position where it does not come into contact with the intermediate transfer body 1 in order to prevent the toner on the surface of the cleaning roller 7 from being deformed due to pressure while the image forming apparatus is stopped or in a standby state. Printing is started, and the intermediate transfer body 1 comes into contact with the intermediate transfer body 1 after starting to rotate. An intermediate transfer member position regulating roller 19 is provided downstream of the cleaning roller 7 in contact with the intermediate transfer member 1.

Hereinafter, each component constituting the present embodiment will be described. The photosensitive drums 4a, 4b, 4c,
As 4d, those having various inorganic photosensitive layers such as Se, a-Si, a-SiC and CdS on the drum surface, or those having various organic photosensitive layers can be used.

The charging devices 3a, 3b, 3c, and 3d are corona dischargers each including a grid and electrode wires. The charging devices 3a, 3b, 3c, and 3d apply a high voltage to the electrode wires and a predetermined voltage to the grid, and The surface of the photosensitive drum is charged uniformly by generating corona discharge between the photosensitive drum and the drum.

The optical scanning device 10 irradiates a laser beam based on an image signal, and scans the laser beam in the main scanning direction of each photosensitive drum by a polygon mirror. This forms an electrostatic latent image.

The developing devices 5a, 5b, 5c, and 5d contain yellow, magenta, cyan, and black toners, respectively, and are in close proximity to the corresponding photosensitive drums 4a, 4b, 4c, and 4d.
They are arranged so as to face each other, and form a visible image by transferring toner to an electrostatic latent image corresponding to each color. The toner used in the image forming apparatus is formed of a thermoplastic binder containing yellow, magenta, cyan, and black dyes, and can be formed by a known material. In this embodiment, a polyester toner having a weight average molecular weight of 540,000, a softening point of 113 ° C., and an average particle size of 7 μm is used.

The primary transfer rollers 6a, 6b, 6c, and 6d are conductive rollers to which a predetermined transfer bias voltage is applied. As a result, an electric field is formed between the photosensitive drum 4 and the intermediate transfer member 1, and the charged toner is transferred to the intermediate transfer member 1.
To be transferred to.

The intermediate transfer member 1 in the form of an endless belt is composed of two layers, a surface layer and a base material layer. For the base material layer, a polyimide film to which carbon black is added is used in order to obtain a proper electric resistivity while having a mechanical strength and heat resistance. Silicon rubber is used for the surface layer in order to obtain releasability and elasticity of the toner.

The heating roller 12 has a heating source such as a Colts lamp inside a metallic cylindrical core having a high thermal conductivity, and heats the heating roller 12 itself to a temperature higher than the melting temperature of the toner. Then, the toner image and the recording paper carried on the intermediate transfer member 1 are heated via the intermediate transfer member 1. Further, a heat-resistant elastic layer made of silicon rubber or the like is provided on the peripheral surface of the heating roller 12 in order to enhance the adhesion between the heating roller 12 and the intermediate transfer body 1.

The pressure roller 17 is pressed against the heating roller 12 via the intermediate transfer body 1 to press the recording paper and the toner image, and has a heating source like the heating roller 12. The toner image and the recording paper carried on the intermediate transfer body 1 are heated from the back side. An elastic layer is provided on the roller surface similarly to the heating roller 12, and is pressed by the heating roller 12 to form a nip portion for performing secondary transfer and fixing at the same time.

The heating plate 16 has a rubber heater attached to the back of an aluminum contact plate as a planar heater, and the contact plate is heated to a temperature higher than the melting temperature of the toner.

The cleaning roller 7 has a resin layer on the surface and is provided with a heater inside. The surface resin layer is formed of the same material as the binder resin of the toner, and the surface temperature is controlled by a heater to generate tackiness. Further, a heater is also provided inside the opposing roller 14 to heat the residual toner on the intermediate transfer body 1 and adjust the temperature, that is, the viscosity, to facilitate the transfer of the toner to the cleaning roller 7. .

Next, the operation of the image forming apparatus will be described. In each of the image units 2a, 2b, 2c, and 2d arranged around the endless belt-shaped intermediate transfer body 1, the photosensitive drums 4a,
The charging devices 3a, 3b, 3c, and 3d respectively charge the charging devices 4b, 4c, and 4d substantially uniformly. Thereafter, laser light that is turned on and off in response to the image signal is irradiated by the optical scanning device 10 to form an electrostatic latent image.

The electrostatic latent images on the photosensitive drums 4a, 4b, 4c and 4d are developed by developing devices 5a, 5b, 5c and 5d containing yellow, magenta, cyan and black toners, respectively. A so-called digital image expressing the density by modulation is formed as a toner image on each of the photosensitive drums 4a, 4b, 4c and 4d. The color toner images are sequentially transferred onto the intermediate transfer body 1 by the primary transfer rollers 6a, 6b, 6c, and 6d so as to be superimposed on each other, and a full-color toner image is formed on the intermediate transfer body 1.

The toner image formed on the intermediate transfer member 1 is
The intermediate transfer body 1 is preheated when passing through a position facing the heating plate 16, and is sent to a nip portion where the heating roller 12 and the pressure roller 17 are opposed. In synchronization with this, the recording paper is fed from the paper tray 21 to the nip by the paper feeding device 20. Then, the toner image is brought into contact with the recording paper, is further heated and melted, is pressed against the recording paper, and the transfer and the fixing are simultaneously performed.

The toner image fused to the recording paper is conveyed between the intermediate transfer body 1 and the recording paper in a state of being in close contact with both, and
When cooled to a temperature below the melting temperature by the cooling device 18, it is aggregated and solidified, and a strong adhesive force is generated between the recording paper and the recording paper. As a result, when the intermediate transfer body 1 is bent at a large curvature at the position where the peeling roller 13 having a small radius of curvature is arranged, the recording paper is separated from the intermediate transfer body 1 together with the toner image by its own rigidity, and the fixed image is fixed. Is discharged onto a discharge tray.

On the other hand, the toner remaining on the surface of the intermediate transfer member 1 adheres to the cleaning roller 7 and is removed. At this time, paper dust has adhered to the intermediate transfer body 1, and this paper dust also adheres to the peripheral surface of the cleaning roller 7 having adhesive force. Then, while such cleaning is repeated, a large amount of paper dust adheres, the adhesive strength is reduced, and the cleaning performance is deteriorated. On the other hand, the toner is supplied so as to cover the peripheral surface of the cleaning roller 7 to recover the adhesive strength.

Next, as described above, the cleaning roller 7
The operation of maintaining the adhesive strength of the above will be described. FIG. 2 is a schematic perspective view showing a state in which a maintenance toner image 30 for restoring the adhesive force on the peripheral surface of the cleaning roller 7 is supplied, and the maintenance toner image 30 on the intermediate transfer body and the transfer to the recording paper. FIG. 7 is a schematic diagram showing a position of an image 35 to be displayed.

The maintenance / management toner image 30 is formed almost uniformly at a concentration of 6 g / m ² on one of the photosensitive drums 4 and is transferred to the intermediate transfer member 1 and then moved by the rotation of the intermediate transfer member. I do. At this time, the maintenance / management toner image 30 comes into contact with the surface of the pressure roller 17, but since the surface of the pressure roller 17 has a high release property, the toner image 30 is transferred from the intermediate transfer body 1 to the pressure roller 17. Without being transferred to the nip position of the cleaning roller 7. Then, the cleaning roller 7 cleans the maintenance toner image 30, whereby a toner layer 31 is formed on the surface of the roller. The length of the maintenance toner image 30 in the process direction is equal to the length of one rotation of the cleaning roller 7, and the width is set to be equal to or greater than the full width of the recording paper to be used. Over the toner layer 31
Can be formed.

FIG. 3 shows the cleaning performance when 100 sheets of paper A having relatively large amount of paper dust and paper C having small amount of paper dust among common copy sheets are passed under the condition that no image formation is performed. And then the maintenance toner image 30
9 shows the result of measuring the recovery status of the cleaning performance when the cleaning roller 7 was supplied to the cleaning roller 7. From the experimental results, 10
By passing 0 sheets, the cleaning performance of the paper A is reduced so that the required performance is not satisfied, and the cleaning performance is reduced even for the paper C having a small amount of paper dust. Paper C that is 2 rotations long
It can be seen that the cleaning performance is restored by supplying the maintenance toner image 30 having a length corresponding to one rotation to the cleaning roller 7.

In view of the above experimental results, the image forming apparatus of this embodiment is set so that the maintenance toner image 30 is supplied once every 50 sheets. That is, 50 images to be transferred to the recording paper are formed, and these are sequentially transferred to the recording paper, and then the maintenance toner image 30 is formed. This maintenance toner image 30 is formed on the photosensitive drum 4 and then transferred to the intermediate transfer body 1 in the same manner as a normal image. When the toner image passes through the nip portion between the heating roller 12 and the pressure roller 17, no recording paper is supplied, and the toner image moves while being carried on the intermediate transfer body 1 and is supplied to the cleaning roller 7. You.

FIG. 4 shows the result of performing a cleaning test each time 50 images are recorded by such an image forming apparatus. The vertical axis indicates the cleaning grade value, and indicates the result of the silent gaze determination of the residual toner. The state from the state where cleaning is completely impossible to the state where cleaning is completely performed is classified into four, and the state where cleaning is completely performed is graded 0, and the state where cleaning is completely impossible is graded 4. Even when paper A with a lot of paper dust is used,
The cleaning grade value is 1 or less, which indicates that the cleaning performance satisfies the required performance.

Next, a description will be given of an image forming apparatus according to an embodiment of the present invention, in which a toner supply amount is selectively increased to a portion to which a large amount of paper dust adheres. For example, in an image forming apparatus capable of using A4 size vertical feed, A4 size horizontal feed, and A3 size vertical feed, an A4 size horizontal feed and an A4 size
A large amount of paper dust adheres to the portion corresponding to the paper end of the 3-size vertical feed and the paper end of the A4-size vertical feed. Therefore,
These portions are set so as to supply more toner.

FIG. 5A shows an example in which the toner supply amount is adjusted by changing the image length of the maintenance toner image 30 to be supplied. When the recording paper 32 comes into contact with the intermediate transfer member 1 as shown in the figure, the length of the maintenance toner image 30 is increased in the circumferential direction only in the portion corresponding to the paper end (for example, the outer circumference 2 of the cleaning roller 7). (A length corresponding to the number of rotations), and more toner is supplied to a corresponding portion of the peripheral surface of the cleaning roller 7.

FIG. 5B shows an example in which the toner supply amount is adjusted by changing the density of the maintenance toner image 30 to be supplied. For the portion corresponding to the edge of the sheet, the toner supply amount can be adjusted by a method of increasing the area ratio of the halftone dot image, a method of overlapping two color toner images, or the like. In the above description, the A4 size and the A3 size are taken as examples. However, the image forming apparatus that can use the A5 size and the B row size paper, and the alignment of the paper is based on the center of the intermediate transfer body 1. Similarly, in the case of the image forming apparatus described above, more toner may be supplied to a portion corresponding to each sheet edge.

As described above, when the supply amount of toner is increased for a part of the width of the cleaning roller 7 in the width direction,
The position at which the toner supply amount is increased can be determined according to the number of sheets used and the sheet size. The image forming apparatus controlled in this way is one embodiment of the invention according to claim 3.

For example, as shown in FIG.
When four sheets have been fed horizontally and the total number of sheets has reached a certain number (in the case of the toner supply interval (a)), the maintenance toner image 30 is positioned at the position of the edge of the A4 portrait sheet. A
The amount of toner is increased at a position which is the end of the sheet for the four-side feeding. On the other hand, in the case where the A4 horizontal feed only (or the A4 vertical feed only) is performed (in the case of the toner supply interval (b)),
Since it is only necessary to respond to the paper edge of A4 landscape feed,
Two portions increase the amount of toner.

The maintenance toner image 30 can be used in whole or in part as a toner image used for image adjustment. This image forming apparatus is an embodiment of the invention described in claim 4. In this image forming apparatus, the detection of the development density is performed by detecting the density of the toner patches formed on the photoconductors 4a, 4b, 4c, and 4d for the respective colors by a sensor. The detection of the image superposition position for each color is performed by detecting the position of the registration toner image transferred onto the intermediate transfer body 1.
Such a toner patch for detecting the development density or the toner image used for detecting the position of the intermediate transfer member is transferred to the intermediate transfer member 1. Then, these toner images are supplied to the peripheral surface of the cleaning roller 7 without being transferred to the recording paper.

The toner patch 33 for detecting the development density and the toner image 34 for positioning are set so as to be formed at positions corresponding to the edges of the sheet on which the toner image is transferred. Are superimposed and transferred on a substantially uniform halftone toner image formed in a range corresponding to the above, and are supplied to a portion of the paper edge portion where there is much paper dust. In this way, by using the toner patch 33 and the alignment toner image 34 as the maintenance toner image of the cleaning roller 7, the toner can be effectively used and the consumption can be reduced.

The maintenance toner image does not need to be continuously formed on the entire circumference of the cleaning roller 7 but may be formed separately. Thus, the image forming apparatus that forms the maintenance toner image is an embodiment of the invention according to claim 5. In the image forming apparatus controlled in this way, for example, the maintenance toner image 30 supplied to the cleaning roller 7 is transferred to the image 3 transferred to the recording paper.
It is divided into a plurality of inter-images of five and formed.
The transfer image 35 is transferred to a recording sheet, but the maintenance toner image 30 formed in the inter-image portion is transferred as it is, and comes into contact with and adheres to the cleaning roller 7.

FIG. 8 shows the formation of a maintenance toner image 30 divided into four parts while forming a plurality of images to be transferred onto A4 landscape-fed paper. By setting the ratio of the diameter (φ) of the roller 7 as shown in the figure, when the four maintenance toner images 30 are attached to the cleaning roller, they cover the entire peripheral surface thereof. Accordingly, it is possible to form a toner image for recovering the cleaning performance and supply the toner image to the cleaning roller 7 at the same time as the image output, and it is possible to reduce the influence on the number of formed images per unit time. .

In the above-described image forming apparatus, the toner used for forming the maintenance toner image 30 can be selected from yellow, magenta, cyan, and black toners as follows. The image forming apparatus controlled in this way is one embodiment of the invention according to claim 6. The developing device that stores the toner of each color has a toner sensor, and detects the remaining amount of toner,
A comparison is made between the toners of the respective colors. Then, as shown in FIG. 9A, when the remaining amount of the yellow toner is the largest, the maintenance toner image 30 is formed using the yellow toner. Further, as shown in FIG. 9B, when the remaining amount of magenta toner is the smallest, the maintenance toner image 30 may be formed using three color toners other than magenta,
Two colors having a large remaining amount of toner, that is, a yellow toner and a cyan toner may be used. As described above, by selecting the toner used for forming the maintenance toner image 30, the consumption of the toner can be averaged, and the frequency of toner replenishment can be reduced. Note that the remaining amount of toner can also be detected by the number of sheets passed since the last supply of toner, the amount of toner in each toner container in the image forming apparatus, the toner concentration in each developing device, and the like.

[0062]

As described above, according to the present invention, it is possible to clean a cleaning member having reduced cleaning performance due to adhesion of paper dust as a result of passing a paper by a simple method without providing a special device. It is possible to recover the performance of the member, that is, to maintain the adhesiveness of the cleaning member.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic perspective view showing a state in which a maintenance toner image for restoring adhesive force is supplied to a peripheral surface of a cleaning roller, and a maintenance toner image on an intermediate transfer member and toner transferred to recording paper; FIG. 3 is a schematic diagram illustrating a position of an image.

FIG. 3 is a diagram showing a state of recovery of cleaning performance by supplying a maintenance toner image.

FIG. 4 is a diagram illustrating a state in which cleaning performance is maintained by supplying a maintenance toner image.

FIG. 5 is a schematic diagram illustrating an example of a form of a maintenance toner image.

FIG. 6 is a schematic diagram illustrating a method for adjusting the form of the maintenance toner image according to the size and number of sheets onto which the toner image has been transferred.

FIG. 7 is a schematic view showing an example in which a part of the maintenance management toner image is used as a development density detection toner patch or an alignment toner image.

FIG. 8 is a schematic diagram illustrating an example in which a maintenance toner image is divided into a plurality of toner images and supplied to a cleaning roller.

FIG. 9 is a diagram illustrating an outline of a method of selecting a toner to be supplied to a cleaning roller.

FIG. 10 is a diagram illustrating a degree of deterioration in cleaning performance when 100 sheets of a plurality of types of copy sheets are passed.

FIG. 11 is a diagram showing the relationship between the amount of paper powder adhering to the cleaning roller surface and the cleaning grade.

[Explanation of symbols]

1 Intermediate transfer member 2a, 2b, 2c, 2d Image forming unit 3a, 3b, 3c, 3d Charging device 4a, 4b, 4c, 4d Photoconductor drum 5a, 5b, 5c, 5d Developing device 6a, 6b, 6c, 6d Primary Transfer Roller 7 Cleaning Roller 10 Optical Scanning Device 11 Drive Roller 12 Heating Roller 13 Peeling Roller 14 Opposing Roller 15 Guide Roller 16 Heating Plate 17 Pressure Roller 18 Cooling Device 19 Intermediate Transfer Body Position Control Roller 20 Paper Feeder 21 Paper Tray 30 Maintain Toner image for management 31 Toner layer 32 Recording paper 33 Toner patch for detecting development density 34 Toner image for positioning 35 Image transferred to recording paper

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 15/20 102 G03G 15/20 102 2H078 15/24 15/24 F term (Reference) 2H027 DA45 DC07 DC10 DC10 DD02 DD05 DE09 EB04 EC03 EC06 ED10 ED16 ED27 EF09 2H030 AB02 AD04 AD17 BB42 BB44 BB46 2H032 AA05 AA15 BA03 BA21 BA23 BA27 BA30 2H033 BE09 2H077 DA04 DA10 DA15 DA42 GA13 2H078 AA01 CC06 DD53 DD57 DD58 EE

Claims (6)

[Claims] An image carrier on which a latent image due to a difference in electrostatic potential is formed on a surface; a developing means for visualizing the electrostatic latent image on the image carrier by attaching toner to the image carrier; An intermediate transfer member having an endless peripheral surface, and a toner image formed on the image carrier is primarily transferred onto the peripheral surface; and a heating unit for heating and melting the toner image on the intermediate transfer member. A pressure-fixing means for pressing the melted toner image onto a recording medium and simultaneously performing secondary transfer and fixing; and a heat-adhesive resin layer provided on an endless peripheral surface,
A cleaning member that is pressed against the intermediate transfer body after the secondary transfer and adheres and removes residual toner to the resin layer, and the toner transferred to the recording medium on the image carrier. In addition to the image, a toner image for maintenance that is not transferred to the recording medium is formed, and after the toner image for maintenance is transferred onto the intermediate transfer body, the recording used over the entire circumference of the cleaning member. An image forming apparatus characterized in that it is set so that the maintenance toner image is adhered to a range not less than the full width of the medium. 2. A range corresponding to the vicinity of both side edges in the width direction of the recording medium, wherein the maintenance management toner image is:
The image forming apparatus according to claim 1, wherein the image forming apparatus is formed so as to increase a toner amount. 3. A recording medium detecting means for detecting the number and size of the recording medium onto which the toner image on the intermediate transfer member has been transferred, and a range for increasing the toner amount of the maintenance toner image is as follows. ,
3. The method according to claim 1, wherein the recording medium detecting unit increases the toner amount in a range corresponding to the vicinity of both side edges of the size of the recording medium in which it is detected that a predetermined number of sheets have been transferred and fixed. 3. The image forming apparatus according to 2. 4. The maintenance toner image according to claim 1, wherein a part of the maintenance management toner image is an image for adjusting image density or adjusting a position where a toner image is formed. An image forming apparatus according to any one of the above. 5. The maintenance / management toner image is formed so as to be divided into a plurality of parts, and when the toner image is attached to a peripheral surface of the cleaning member, the toner image is attached to the entire periphery of the cleaning member without gaps. The image forming apparatus according to claim 1, wherein: 6. The developing device has a plurality of developing devices each containing a toner of a different color, the developing device includes a toner sensor for detecting an amount of toner contained in each of the developing devices, The management toner image is formed by one developing device having a large remaining amount of toner detected by the toner sensor or a plurality of developing devices sequentially selected from those having a large remaining amount. Claims 1 to 5
The image forming apparatus according to any one of the above.