JP3049591B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer method in which a plurality of toner images of different colors are sequentially formed on a photosensitive drum, and the plurality of toner images formed on the photosensitive drum are transferred on a transfer drum. The present invention relates to an image forming apparatus, such as an electrophotographic copying machine or a printer, which forms an image by transferring images in a state of being sequentially superimposed on a transfer material. The present invention relates to a technique for preventing a malfunction.

[0002]

2. Description of the Related Art Conventionally, as an image forming apparatus using a transfer drum of this type, a plurality of toner images having different colors such as cyan, magenta, yellow, and black are sequentially formed on a photosensitive drum. There is a configuration in which a plurality of toner images formed on a drum are sequentially transferred onto a transfer material such as a transfer sheet carried on a transfer drum in a state of being superimposed thereon to form an image. Then, in this image forming apparatus, after a predetermined number of toner images are multiplexly transferred onto the transfer material adsorbed on the transfer drum, the transfer material is peeled off from the surface of the transfer drum, and is transferred onto the transfer material by a fixing device. The toner image is fixed. Further, in the image forming apparatus, if necessary, the transfer material having the toner image formed on one side is again turned upside down and fed again.
Duplex copying is also possible.

At this time, the image forming apparatus detects whether or not the transfer material is held in a proper state on the surface of the transfer drum, or whether or not the transfer material is surely separated from the surface of the transfer drum. A transfer material conveyance failure detection unit is used. Further, in the above-described image forming apparatus, since a floating toner or an external additive of toner or paper powder such as transfer paper as a transfer material adheres to the surface of the transfer drum, a cleaning device for cleaning the surface of the transfer drum is used. Have been.

On the surface of the transfer drum 100, a transfer material 101 supplied from a sheet cassette (not shown) is pressed against the surface of the transfer drum 100 by a suction roll 102 as shown in FIG. The transfer material 101 is electrostatically adsorbed by being charged by the adsorbing corotron 103 from the back side of the drum 100. After the toner image formed on the photosensitive drum 104 is sequentially transferred to the transfer material 101 adsorbed on the surface of the transfer drum 100, the transfer drum 10 is
0, the toner image is fixed on the transfer material 101 by the fixing device 106, and the image forming process ends.

At this time, a jam sensor 107 for detecting whether or not the transfer material 101 is attracted to the surface of the transfer drum 100 is provided on the outer periphery of the transfer drum 100 at a downstream side of the attraction roller 102, and a photosensitive member. Downstream of the nip portion with the drum 104, a jam sensor 108 for detecting whether or not the transfer material 101 is held on the surface of the transfer drum 100, and downstream of the peeling device 105,
A jam sensor 109 for detecting whether or not 01 has been separated from the surface of the transfer drum 100 is provided. Further, on the outer periphery of the transfer drum 100, for example,
As disclosed in JP-A-62-280883, a cleaning brush 110 for cleaning the surface of the transfer drum 100 is provided.

[0006]

However, the prior art described above has the following problems. That is, in the case of the above-described conventional image forming apparatus, as shown in FIG. 14, the transfer material 101 on which a plurality of toner images having different colors such as cyan, magenta, yellow, and black are transferred.
In order to prevent the toner from being offset onto the transfer material 101 when the toner is fixed by the fixing device 106, a release agent such as silicone oil, which is larger in amount than a normal black and white copy, is used. The agent also adheres to the transfer material 101. Therefore, in the case of the above-described image forming apparatus, especially when performing double-sided copying, the surface of the transfer material 101 on which the toner image is formed comes into contact with the surface of the transfer drum 100, and the separation adhered to the transfer material 101 The mold agent adheres to the surface of the transfer drum 100. Then, on the surface of the transfer drum 100,
The release agent adhered to the surface of the transfer drum 100 functions as an adhesive, and the floating toner or an external additive of the toner, or paper powder such as transfer paper as the transfer material 101 adheres.

As described above, the floating toner adhered to the surface of the transfer drum 100, the external additive of the toner, or the transfer material 1
The paper powder such as transfer paper as the toner particles 00, particularly the external additive and paper powder of the toner having a small particle size cannot be sufficiently cleaned by the cleaning brush 110, and the transfer drum 100
Is gradually accumulated on the surface of the transfer drum 100, and the surface of the transfer drum 100 gradually becomes cloudy. As described above, the transfer drum 100
When the surface of the transfer drum 100 becomes cloudy, the detection levels of the jam sensors 107, 108, and 109 disposed on the outer periphery of the transfer drum 100 decrease, and erroneous detection occurs. As a result, if the transfer film 100a on the surface of the transfer drum 100 is not replaced, the device will not operate normally, so that the transfer film 100a
There is a problem that the exchange interval of the first time is advanced. Although such a problem is particularly remarkable when a two-sided copy is performed in the image forming apparatus, even when the two-sided copy is not performed, the toner external additive and paper powder gradually accumulate on the surface of the transfer drum, and the transfer is performed. The surface of the drum gradually becomes cloudy, causing the same problem.

Incidentally, in the image forming apparatus using the transfer drum, in addition to the transfer material detecting means such as a jam sensor 107 for detecting the conveyance state of the transfer material 101 on the transfer drum 100, the transfer drum 100 Density detecting means for transferring the test patch thereon and detecting the toner density of the test patch on the transfer drum 100 is also used. White turbidity on the surface of the transfer drum 100 is erroneously detected when detecting the toner density of the test patch. It may cause.

SUMMARY OF THE INVENTION Therefore, the present invention has been made to solve the above-mentioned problems of the prior art. It is an object of the present invention to provide a simple structure for detecting a transfer material when the surface of a transfer drum becomes cloudy. Another object of the present invention is to provide an image forming apparatus capable of preventing erroneous detection of a density detecting unit and preventing an advance of a transfer film exchange interval.

[0010]

According to a first aspect of the present invention, there is provided an image forming apparatus, wherein a plurality of toner images having different colors are sequentially formed on an image carrier, and the toner images are formed on the image carrier. In an image forming apparatus for forming an image by sequentially transferring a plurality of toner images on a transfer material carried on a transfer material carrier in a superimposed state, a transfer state of the transfer material on the transfer material carrier And a density detecting means for detecting the toner density on the transfer material carrier, and at least at the same position as the transfer material detecting means or the density detecting means in the axial direction of the transfer material carrier. A cleaning unit for cleaning the transfer material carrier is provided, and an axial length of the cleaning unit is configured to be wider than a beam spot diameter of the detection unit and narrower than an effective image width. Cleaning means is configured to be separable with respect to said transfer material carrying member.

According to a second aspect of the present invention, there is provided an image forming apparatus, wherein a plurality of toner images having different colors are sequentially formed on an image carrier, and the plurality of toner images formed on the image carrier are formed. In an image forming apparatus for forming an image by sequentially transferring images onto a transfer material carried on a transfer material carrier in a state where the transfer material is transferred on the transfer material carrier. Density detecting means for detecting the toner density on the transfer material carrier, or a transfer material carrier provided at least at the same position as the transfer material detecting means or density detector in the axial direction of the transfer material carrier A cleaning means for cleaning the cleaning means, wherein the length of the cleaning means in the axial direction is wider than the beam spot diameter of the detection means and not more than 20 mm; And it is configured so as to be separable with respect to said transfer material carrying member.

Further, according to a third aspect of the present invention, in the image forming apparatus, a plurality of toner images having different colors are sequentially formed on the image carrier, and the plurality of toner images formed on the image carrier are formed. Cleaning is performed over the effective image width in an image forming apparatus in which an image is formed by sequentially transferring the transfer material onto a transfer material carried on the transfer material carrier in an overlapping state. Means,
Transfer material detecting means for detecting the transfer state of the transfer material on the transfer material carrier or density detecting means for detecting the toner concentration on the transfer material carrier; and the transfer material detecting means in the axial direction of the transfer material carrier Alternatively, a second cleaning means for cleaning the transfer material carrier provided at least at the same position as the density detecting means is provided so as to be able to come into contact with and separate from the transfer material carrier, and the axial length of the cleaning means is determined by the detection. The second cleaning unit is configured to be wider than the beam spot diameter of the unit and narrower than the effective image width, and the second cleaning unit is arranged upstream of the first cleaning unit.

Further, according to a fourth aspect of the present invention, in the image forming apparatus, a plurality of toner images having different colors are sequentially formed on the image carrier, and the plurality of toner images formed on the image carrier are formed. In an image forming apparatus for forming an image by transferring images in a state of being sequentially superimposed on a transfer material carried on a transfer material carrier, a first method for cleaning the transfer material carrier over an effective image width is provided. Cleaning means, transfer material detecting means for detecting the transfer state of the transfer material on the transfer material carrier or density detecting means for detecting the toner concentration on the transfer material carrier, and A second cleaning means for cleaning the transfer material carrier provided at least at the same position as the transfer material detection means or the density detection means, which is provided so as to be capable of coming into contact with and separating from the transfer material carrier; With the axial length of the ring means is constructed in the following wider 20mm than the beam spot diameter of said detecting means, said second cleaning means,
It is configured to be disposed on the upstream side of the first cleaning unit.

Further, in the image forming apparatus according to a fifth aspect of the present invention, a plurality of toner images having different colors are sequentially formed on the image carrier, and the plurality of toner images formed on the image carrier are formed. In an image forming apparatus for forming an image by sequentially transferring images onto a transfer material carried on a transfer material carrier in a state where the transfer material is transferred on the transfer material carrier. Density detecting means for detecting the toner density on the transfer material carrier, or a transfer material carrier provided at least at the same position as the transfer material detecting means or density detector in the axial direction of the transfer material carrier A cleaning means for cleaning the transfer material carrier is provided so as to be able to approach and separate from the transfer material carrier, and an axial length of the cleaning means is wider than a beam spot diameter of the detecting means and narrower than an effective image width. And which, the cleaning unit is configured to interlock to toward and away from the members related to the feeding and the separation of the transfer material on the transfer material carrying member.

According to a sixth aspect of the present invention, in the image forming apparatus, a plurality of toner images having different colors are sequentially formed on the image carrier, and the plurality of toner images formed on the image carrier are formed. In an image forming apparatus for forming an image by sequentially transferring images onto a transfer material carried on a transfer material carrier in a state where the transfer material is transferred on the transfer material carrier. Density detecting means for detecting the toner density on the transfer material carrier, or a transfer material carrier provided at least at the same position as the transfer material detecting means or density detector in the axial direction of the transfer material carrier A cleaning means for cleaning the transfer material carrier is provided so as to be able to approach and separate from the transfer material carrier, and the length of the cleaning means in the axial direction is wider than the beam spot diameter of the detection means and is set to 20 mm or less. The cleaning unit is configured to interlock to toward and away from the members related to the feeding and the separation of the transfer material on the transfer material carrying member.

Further, according to a seventh aspect of the present invention, in the image forming apparatus according to any one of the first to sixth aspects, the cleaning means or the cleaning means is provided.
The second cleaning means is provided on the transfer assisting member, and is configured to clean the inner surface of the transfer material carrier during the transfer operation.

An image forming apparatus according to an eighth aspect of the present invention is the image forming apparatus according to any one of the first to sixth aspects, wherein the cleaning means or the second cleaning means is provided .
Cleaning means is configured to be disposed on the transfer material suction-aid member.

Further, according to a ninth aspect of the present invention, in the image forming apparatus according to any one of the first to sixth aspects, the cleaning means or
The second cleaning unit is configured to be provided in the first inner cleaning unit that cleans the transfer material carrier.

According to a tenth aspect of the present invention, in the image forming apparatus, a plurality of toner images having different colors are sequentially formed on the image carrier, and the plurality of toner images formed on the image carrier are formed. In an image forming apparatus for forming an image by transferring an image sequentially onto a transfer material carried on a transfer material carrier in a state of being superimposed thereon, a transfer state of the transfer material on the transfer material carrier is detected. Transfer material detecting means or density detecting means for detecting the toner concentration on the transfer material carrier, and transfer material peeling means for contacting the surface of the transfer material carrier and peeling the transfer material from the transfer material carrier. The transfer material peeling means is disposed at least at the same position as the transfer material detection means or the density detection means in the axial direction of the transfer material carrier, so as to make at least line contact with the surface of the transfer material carrier in the axial direction. did Than it is.

Further, in the image forming apparatus according to an eleventh aspect of the present invention, in the image forming apparatus according to the tenth aspect, the transfer material peeling means is arranged to rotate around the circumference of the transfer material carrier during the peeling operation. It is configured to contact the surface of the transfer material carrier in all directions.

According to a twelfth aspect of the present invention, in the image forming apparatus of the tenth aspect, the transfer material peeling means is provided in a circumferential direction of the transfer material carrier during the peeling operation. In contact with the surface of the transfer material carrier only in the detection area of the transfer material detection means for detecting the transfer state of the transfer material on the transfer material support or the density detection means for detecting the toner density on the transfer material support It is configured so that

According to a thirteenth aspect of the present invention, in the image forming apparatus, a plurality of toner images having different colors are sequentially formed on the image carrier, and the plurality of toner images formed on the image carrier are formed. In an image forming apparatus for forming an image by sequentially transferring images onto a transfer material carried on a transfer material carrier in a state where the transfer material is transferred on the transfer material carrier. A transfer material adsorbing auxiliary member for adsorbing the transfer material on the surface of the transfer material support member; Are arranged at least at the same position as the transfer material detecting means or the density detecting means in the axial direction of the transfer material carrier so as to make at least line contact with the surface of the transfer material carrier in the axial direction.

Further, according to a fourteenth aspect of the present invention, in the image forming apparatus, a plurality of toner images having different colors are sequentially formed on the image carrier, and the plurality of toner images formed on the image carrier are formed. In an image forming apparatus for forming an image by transferring an image sequentially onto a transfer material carried on a transfer material carrier in a state of being superimposed thereon, a transfer state of the transfer material on the transfer material carrier is detected. A transfer material detecting means or a density detecting means for detecting a toner concentration on the transfer material carrier; and an inner peeling means for contacting an inner surface of the transfer material carrier and peeling the transfer material from the transfer material carrier. Wherein the inner peeling means is disposed at least at the same position as the transfer material detecting means or the density detecting means in the axial direction of the transfer material carrier so as to make at least line contact with the surface in the axial direction of the transfer material carrier. A.

[0024]

According to a first aspect of the present invention, there is provided an image forming apparatus, wherein a transfer material detecting means for detecting a transfer state of a transfer material on a transfer material carrier or a density detection for detecting a toner density on the transfer material carrier. Means, and cleaning means for cleaning a transfer material carrier provided at least at the same position as the transfer material detection means or the density detection means in the axial direction of the transfer material carrier, and an axial length of the cleaning means. Is configured to be wider than the beam spot diameter of the detection unit and narrower than the effective image width, and the cleaning unit is configured to be able to contact and separate from the transfer material carrier. The transfer is realized by a very simple structure of being arranged at least at the same position as the transfer material detecting means or the density detecting means in the axial direction of the transfer material carrier. Cloudiness of the surface of the carrier can be prevented,
It is possible to prevent erroneous detection of the transfer material detecting means or the density detecting means.

The length of the cleaning means in the axial direction is wider than the beam spot diameter of the detection means and narrower than the effective image width. Since the cleaning can be surely performed and is configured to be narrower than the effective image width, the area corresponding to the detecting unit can be effectively cleaned. Further, since the cleaning means can be brought into contact with and separated from the transfer material carrier, the toner image transferred onto the transfer material is not damaged.

According to a second aspect of the present invention, there is provided an image forming apparatus, wherein a transfer material detecting means for detecting a transfer state of the transfer material on the transfer material carrier or a toner concentration on the transfer material carrier. A density detecting means, and a cleaning means for cleaning a transfer material carrier provided at least at the same position as the transfer material detecting means or the density detecting means in the axial direction of the transfer material carrier; The length is wider than the beam spot diameter of the detecting means and is equal to or less than 20 mm, and the cleaning means is configured to be able to contact and separate from the transfer material carrier. The length corresponding to the beam spot diameter can be reliably cleaned, and, as has been clarified in the experiments of the present inventors, the length is equal to the beam spot diameter. With a cleaning efficiency can be prevented from decreasing as in the case of over 0 mm, it is possible to create a cleaning means compact, there is a merit in terms of cost.

Further, according to a third aspect of the present invention, there is provided the image forming apparatus, wherein the first cleaning means for cleaning the transfer material carrier over the effective image width, and a transfer state of the transfer material on the transfer material carrier. And a density detecting means for detecting the toner density on the transfer material carrier, and at least at the same position as the transfer material detecting means or the density detecting means in the axial direction of the transfer material carrier. A second cleaning means for cleaning the transfer material carrier is provided so as to be capable of coming into contact with and separating from the transfer material carrier, and the axial length of the cleaning means is wider than the beam spot diameter of the detection means and is greater than the effective image width. And the second cleaning means is provided with the first cleaning means.
Is arranged on the upstream side of the cleaning means, so that the same action and effect as those of the first aspect of the invention can be obtained, and of course, it is removed by the second cleaning means. Toner, external additives, paper powder, and the like can be cleaned by the first cleaning means located downstream.

Further, in the image forming apparatus according to a fourth aspect of the present invention, the first cleaning means for cleaning the transfer material carrier over the effective image width, and the transfer of the transfer material on the transfer material carrier. A transfer material detecting means for detecting a state or a density detecting means for detecting a toner density on the transfer material carrier; and a transfer material detecting means or a density detecting means provided at least at the same position in the axial direction of the transfer material carrier. A second cleaning means for cleaning the transfer material carrier is provided so as to be able to come into contact with and separate from the transfer material carrier, and the axial length of the cleaning means is wider than the beam spot diameter of the detection means to 20 mm or less. The second cleaning unit is configured to be disposed upstream of the first cleaning unit. Has both the action and effects of the invention described in the item 2 according to claim 3 wherein.

Further, in the image forming apparatus according to a fifth aspect of the present invention, a transfer material detecting means for detecting a transfer state of the transfer material on the transfer material carrier or a toner concentration on the transfer material carrier is detected. A density detecting means and a cleaning means for cleaning a transfer material carrier provided at least at the same position as the transfer material detection means or the density detection means in the axial direction of the transfer material carrier are brought into contact with the transfer material carrier. The cleaning unit is configured so that the length in the axial direction of the cleaning unit is wider than the beam spot diameter of the detection unit and narrower than the effective image width, and the cleaning unit supplies the transfer material on the transfer material carrier. Since it is configured to contact and separate with members related to feeding and peeling, in the invention according to claim 1, the cleaning means can be used without using a special member. From hinder the transfer material on Utsushizai carrier can be reliably prevented.

According to a sixth aspect of the present invention, there is provided an image forming apparatus, wherein a transfer material detecting means for detecting a transfer state of the transfer material on the transfer material support or a toner concentration on the transfer material support is detected. A density detecting means and a cleaning means for cleaning a transfer material carrier provided at least at the same position as the transfer material detection means or the density detection means in the axial direction of the transfer material carrier are brought into contact with the transfer material carrier. The cleaning unit is configured so that the length of the cleaning unit in the axial direction is wider than the beam spot diameter of the detection unit and is equal to or less than 20 mm, and the cleaning unit feeds and separates the transfer material on the transfer material carrier. Since it is configured so as to contact and separate in conjunction with the members related to (1), it has both the functions and effects of the inventions described in claims (2) and (5).

Further, in the image forming apparatus according to a tenth aspect of the present invention, a transfer material detecting means for detecting a transfer state of the transfer material on the transfer material carrier or a toner concentration on the transfer material carrier is detected. A density detecting unit, and a transfer material peeling unit that comes into contact with the surface of the transfer material carrier to peel off the transfer material from the transfer material carrier. The transfer material peeling unit is provided in the axial direction of the transfer material carrier. At least at the same position as the transfer material detecting means or the density detecting means in the above, so as to make at least line contact with the surface in the axial direction of the transfer material carrier, so that the transfer material carrier is not added without adding a new member. The surface of the transfer material carrier is externally added to the toner by scraping off the external additive of the toner or fine particles such as paper powder attached to the surface of the transfer material carrier by the transfer material peeling means that is in linear contact with the surface of the toner. And paper powder Thus it is possible to prevent the white turbidity, it is possible to prevent erroneous detection of the transfer material detecting means or the concentration-detecting means.

According to a thirteenth aspect of the present invention, there is provided an image forming apparatus, wherein a transfer material detecting means for detecting a transfer state of the transfer material on the transfer material carrier or a toner concentration on the transfer material carrier. A density detection unit, and a transfer material adsorption auxiliary member for adsorbing the transfer material on the surface of the transfer material support, wherein the transfer material adsorption auxiliary member is a transfer material detection unit in the axial direction of the transfer material support or Since the transfer material carrier is arranged at least at the same position as the density detecting means so as to make at least line contact with the surface in the axial direction of the transfer material carrier, the same operation and effect as those of the tenth aspect are obtained.

Further, according to an image forming apparatus of the present invention, there is provided a transfer material detecting means for detecting a transfer state of a transfer material on a transfer material carrier or a toner concentration on the transfer material carrier. Density detecting means, and an inner peeling means that comes into contact with the inner surface of the transfer material carrier to peel off the transfer material from the transfer material carrier. The inner peeling means is provided in the axial direction of the transfer material carrier. 11. The same operation as the invention according to claim 10, since the transfer material carrier is arranged at least at the same position as the transfer material detection means or the density detection means so as to make at least line contact with the surface in the axial direction of the transfer material carrier. -Has an effect.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiment.

FIG. 8 shows an embodiment of a multi-transfer type digital color image forming apparatus as an image forming apparatus according to the present invention.

In FIG. 8, reference numeral 1 denotes a main body of the digital color image forming apparatus, and an image reading apparatus 3 (Image Input) for reading an image of the original 2 is provided at an upper end in the main body 1 of the digital color image forming apparatus. Ter
minal) is arranged. This image reading device 3
Illuminates the image of the original 2 placed on the platen glass 4 by the platen cover 5 with the light source 6, and reflects the reflected light image of the original 2 on the first and second scanning mirrors 7 and 8. The CCD sensor 10 is scanned and exposed through the imaging lens 9 and the original 2 is scanned by the CCD sensor 10.
Is read at a predetermined dot density (for example, 16 dots / mm).

The color material reflected light image of the original 2 read by the image reading device 3 is, for example, original reflectance data of three colors of red (R), green (G), and blue (B) (8 bits each). As the image processing device 12 (Image Process)
The image processing apparatus 12 transmits the reflectance data of the document 2 to the shading correction, the position shift correction, the lightness / color space conversion, the gamma correction, the frame erasure, the color / movement editing, and the like. Predetermined image processing is performed.

The image data subjected to the predetermined image processing by the image processing device 12 as described above includes black (K), yellow (Y), magenta (M), and cyan (C) (8 bi each).
t) is converted into the original color material gradation data of the three colors ROS1
5 (Raster Output Scanner), and the ROS 15 performs image exposure with laser light in accordance with the original color material gradation data.

As shown in FIG. 8, the ROS 15 modulates the semiconductor laser 16 according to the original color material gradation data 14, and emits the laser beam LB from the semiconductor laser 16 according to the gradation data 14. . The laser light LB emitted from the semiconductor laser 16 is applied to a rotating polygon mirror 17.
The light is deflected and scanned, and is scanned and exposed on the photosensitive drum 20 via the reflection mirror 18.

The photosensitive drum 20 on which the laser light LB is scanned and exposed by the ROS 15 is driven to rotate at a predetermined speed in a direction indicated by an arrow by a driving means (not shown). The surface of the photosensitive drum 20 is
After being charged to a predetermined potential by the charging corotron 21 in advance, an electrostatic latent image is formed by scanning and exposing a laser beam LB in accordance with document color material gradation data. The electrostatic latent images formed on the photoreceptor drum 20 include four color developing units 22K, 22Y, 22M, 22C of black (K), yellow (Y), magenta (M), and cyan (C).
Are sequentially developed by a rotary type developing device 22 provided with a toner image having a predetermined color.

The toner image formed on the photosensitive drum 20 is transferred to a transfer sheet 2 as a transfer material held on a transfer drum 23 disposed adjacent to the photosensitive drum 20.
4 is sequentially transferred by the charging of the transfer corotron 25. As shown in FIG. 8, the transfer material 24 includes a plurality of paper feed cassettes 2 arranged at a lower portion in the image forming apparatus main body 1.
8, 29, and 30 are fed by a feed roll 31 and can also be fed from a manual feed tray 38 disposed on a side surface outside the image forming apparatus main body 1. Transfer drum 2 by the transfer roller 32
3 is conveyed to the respective surfaces. The transfer material 24 is held on the surface of the transfer drum 23 while being electrostatically attracted to the surface of the transfer drum 23 by the charging of the charging corotron 33. The manual feed tray 3
8, transparent OHP sheets and the like for overhead projectors can be fed in addition to non-standard-size transfer sheets, and images can be formed on OHP sheets and the like. Also, from the manual feed tray 38,
By feeding the paper with the transfer material 24 having an image formed on one side upside down, double-sided copying is possible.

The transfer material 24 onto which the toner image of a predetermined number of colors has been transferred from the photosensitive drum 20 is separated from the surface of the transfer drum 23 by the charging of the separation corotron 34 and then conveyed to the fixing device 35. Then, the toner image is fixed on the transfer material 24 by heat and pressure by the fixing device 35, and is discharged onto the paper discharge tray 36, thereby completing the color image forming process.

In FIG. 8, reference numeral 37 denotes a charge removing corotron for removing charges from the transfer drum 23.

FIG. 1 is a block diagram showing the image forming section of the digital color image forming apparatus of the multiple transfer system.

In FIG. 1, reference numeral 20 denotes the photosensitive drum, and a transfer drum 23 as a transfer material carrier is provided so as to come into contact with the surface of the photosensitive drum 20.
The transfer drum 23 is driven to rotate at the same speed as the peripheral speed of the photosensitive drum 20 by a drive mechanism (not shown). As shown in FIG. 9, the transfer drum 23 includes a pair of ring members 40, 40 arranged at both ends in the axial direction, and a ring member 4.
A drum-shaped frame having a tie bar plate 41 as a connecting member for connecting 0 and 40 to each other is provided. A circumferential direction of a transfer film 42 made of a dielectric film such as polyethylene terephthalate or polyvinylidene fluoride is provided on the tie bar plate 41. Of the transfer film 42 is fixed to the tie bar plate 41, while the front end edge 42a of the transfer film 42 is wound around the frame along the outer peripheral surfaces of the ring members 40, 40. And is formed in a hollow cylindrical shape.

As shown in FIG. 8, the transfer drum 23 has a plurality of sheet cassettes 28, 29,
The transfer material 24 is supplied from one of the cassettes 30, and the transfer material 24 is pressed against the surface of the transfer drum 23 by the suction roll 43, and
Is charged by a suction corotron 33 from the rear surface side of the transfer drum 23, and is electrostatically sucked onto the transfer film 42 of the transfer drum 23. The transfer material 2 adsorbed on the transfer drum 23
4, the black (K), yellow (Y), magenta (M), and cyan (C) toner images sequentially formed on the photosensitive drum 20 are transferred by charging the transfer corotron 25.

Then, the transfer material 24 onto which the toner images of a predetermined number of colors have been transferred from the photosensitive drum 20 is separated from the peeling device 4.
After being separated from the surface of the transfer drum 23 by the transfer roller 4, the toner image is conveyed to a fixing device 35 via a conveyance guide 45, and the toner image is transferred by the fixing roller 35a and the pressure roller 35b of the fixing device 35 by heat and pressure. The sheet is fixed thereon, and is discharged onto a discharge tray 36 outside the apparatus by a fuser outlet roll 46.

In this embodiment, the transfer material detecting means for detecting the transfer state of the transfer material on the transfer material support or the density detecting means for detecting the toner density on the transfer material support is provided. Transfer material peeling means for peeling the transfer material from the transfer material carrier in contact with the surface of the body,
The transfer material peeling means is disposed at least at the same position as the transfer material detection means or the density detection means in the axial direction of the transfer material carrier, and is arranged so as to make at least line contact with the surface in the axial direction of the transfer material carrier. It is configured.

That is, as shown in FIG. 1, on the outer periphery of the transfer drum, the transfer material
A first jam sensor 50 for detecting whether or not the photosensitive drum 4 is attracted to the surface of the transfer drum 23;
A second jam sensor 51 for detecting whether or not the transfer material 24 is held on the surface of the transfer drum 23 without moving to the photoconductor drum 20 side, on the downstream side of the nip portion with zero.
And a third downstream of the peeling device 44 for detecting whether or not the transfer material 24 has been peeled from the surface of the transfer drum 23.
And the jam sensor 52 are disposed. The first, second, and third jam sensors 50, 51, and 52 have a diameter of, for example, 5 m toward the surface of the transfer drum 23.
m or less, and a spot light having a diameter of about 3 mm is radiated, and diffusely reflected light and specularly reflected light from the surface of the transfer drum 23 are detected, thereby optically transferring the transfer material onto the surface of the transfer drum 23. The one that detects whether or not 24 is held is used. The first, second, and third jam sensors 50, 51, and 52 are all disposed at the same position along the axial direction of the transfer drum 23, as shown in FIG.

In the digital color image forming apparatus using the transfer drum, the transfer material 2 on the transfer drum 23 is used.
In addition to the transfer material detecting means such as the jam sensor 50 for detecting the conveyance state of No. 4, a test patch is transferred onto the transfer drum 23 as necessary, and the toner density of the test patch on the transfer drum 23 is detected. A concentration detecting means is also used.

As shown in FIG. 1, a peeling finger 53 is disposed on the surface of the transfer drum 23 so as to come into contact with the transfer drum 23 at a predetermined timing. Is pressed radially outward from the inside at a predetermined timing to deform the transfer film 42, and a peeling inner pressing member 54 for facilitating the peeling of the transfer material 24 is provided. Further, a separation corotron 47 is disposed on the upstream side of the separation finger 53 of the transfer drum 23 for removing static electricity from the transfer material 24 and facilitating separation of the transfer material 24. The peeling finger 53 is formed of an elastic member such as engineering plastic such as polycarbonate or hard rubber, but may be formed of metal. further,
As shown in FIG. 3, the peeling finger 53 is formed in a generally wedge-shaped section with a wide width.
Are formed flat. Further, as shown in FIG. 4, the tip 53b of the peeling finger 53 is formed linearly along the axial direction of the transfer drum 23, and the side end of the peeling finger 53 on the transfer paper contact surface. Reference numeral 53c is set so that the width of the transfer material 24 increases in a tapered shape in the traveling direction of the transfer material 24 after peeling. The tip 53b of the peeling finger 53 comes into contact with the surface of the transfer drum 23 with a width of 6 mm, for example. Further, as shown in FIG. 5, the peeling finger 53 is provided along the first, second,
It is arranged at the same position as the detection position of the third jam sensor.

The peeling finger 53 configured as described above
As shown in FIG. 6, a base end portion 53e is fixed to a rotating shaft 54 which is supported on the front and rear frames of the apparatus. By rotating the rotating shaft 54 at a predetermined timing, The distal end 53b of the peeling finger 53 comes into contact with the surface of the transfer drum 23. Also,
As shown in FIG. 7, on both sides of the peeling finger 53, peeling guide members 56 fixed to a support 55 are arranged.

As shown in FIG. 1, a cleaning device 57 for cleaning the surface of the transfer film 42 is disposed outside the transfer drum 23. The cleaning device 57 includes a cleaning brush 58 whose surface moves in a direction opposite to the rotation direction of the transfer drum 23 at a predetermined number of rotations.
8, the surface of the transfer film 42 is cleaned. The rotation direction of the cleaning brush 58 may be set to the same direction as the rotation direction of the transfer drum 23. Here, an appropriate nip width between the cleaning brush 51 and the transfer film 42 may be 1 mm or more.

In the image forming apparatus according to this embodiment having the above-described configuration, it is possible to prevent erroneous detection of the transfer material conveyance failure detecting means when the surface of the transfer drum becomes cloudy with a simple configuration as follows. In addition, the transfer film exchange interval is prevented from being advanced.

That is, in the image forming apparatus according to this embodiment, as shown in FIG. 1, black (K), yellow (Y), magenta (M),
After the cyan (C) toner image is sequentially multiplex-transferred with the rotation of the transfer drum 23 onto the transfer material 24 adsorbed on the transfer drum 23, the toner image of this predetermined number of colors is transferred. The transferred transfer material 24 is peeled off from the surface of the transfer drum 23 by a peeling device 44, and a fixing process is performed by a fixing device 35.

In the above-described image forming apparatus, if necessary, the transfer material 24 having the toner image formed on one side is fed again from the manual feed tray 38 with the front and back reversed.
Duplex copying is also possible. At this time, in this image forming apparatus, the transfer material 24 on which a plurality of toner images having different colors such as cyan, magenta, yellow, and black are transferred,
When fixing is performed by the fixing device 35, the toner is transferred to the transfer material 24.
In order to prevent upward offset, a larger amount of release agent such as silicone oil is used than in a normal black and white copy, and this release agent adheres to the transfer material 24 as well. Therefore, in the case of the above-described image forming apparatus, especially when performing double-sided copying, the surface of the transfer material 24 on which the toner image is formed comes into contact with the surface of the transfer drum 23, and the separation adhered on the transfer material 24 is performed. The mold agent adheres to the surface of the transfer drum 23. Then, on the surface of the transfer drum 23, the release agent adhered to the surface of the transfer drum 23 serves as an adhesive, and an external additive of the floating toner or the toner, or a transfer paper 24 as the transfer material 24. Paper dust etc. adhere. As described above, the external additive of the floating toner or the toner attached to the surface of the transfer drum 23, or the paper powder of the transfer paper or the like as the transfer material 24, particularly the external additive or the paper powder of the toner having a small particle diameter, The cleaning brush cannot perform sufficient cleaning and accumulates gradually on the surface of the transfer drum 23, and the surface of the transfer drum 23 gradually becomes cloudy.

In this embodiment, however, FIGS.
As shown in FIG.
Are arranged at the same positions as the positions of the first, second, and third jam sensors 50, 51, and 52 along the axial direction. Therefore, even when floating toner or an external additive of toner or paper powder adheres to the surface of the transfer drum 23, the external additive or paper powder of the floating toner or toner adhered to the surface of the transfer drum 23 is transferred. The surface of the transfer drum 23 can be prevented from being clouded by the peeling finger 53 that appropriately contacts the surface of the drum 23. Therefore, the first, second, and third jam sensors 5 that detect the transfer material 24 held on the surface of the transfer drum 23 become turbid on the surface of the transfer drum 23.
0, 51, 52 can be prevented from being erroneously detected,
The exchange interval of the transfer film 42 can be prevented from being advanced, and the reliability of the device can be improved.

In this embodiment, the first, second, and third jam sensors 50, 51, and 52 for detecting a defective transfer state of the transfer material 24 with respect to the transfer drum 23 come into contact with the surface of the transfer drum 23. Transfer material 24 to transfer drum 2
And a peeling finger 53 that peels from the top of the transfer drum 23 at the same position as the first, second, and third jam sensors 50, 51, and 52 in the axial direction of the transfer drum 23. 23 is arranged so as to make at least line contact with the surface in the axial direction of the transfer drum 23, so that the peeling finger 53 that makes line contact with the surface of the transfer drum 23 can remove toner adhering to the surface of the transfer drum 23 without adding a new member. By scraping fine particles such as external additives and paper dust, the surface of the transfer drum 23 can be prevented from becoming cloudy due to external additives of toner, paper dust, and the like. Jam sensors 50, 51,
52 can be prevented from being erroneously detected.

Embodiment 2 FIG. 10 shows Embodiment 2 of the present invention. The same parts as those in the above embodiment are denoted by the same reference numerals and described.
This embodiment includes a conveyance failure detection unit that detects a conveyance state of the transfer material with respect to the transfer material carrier, and a blade-like cleaning unit that cleans the surface of the transfer material carrier. The means is arranged at the same position as the conveyance failure detecting means in the axial direction of the transfer material carrier.

That is, in this embodiment, as shown in FIG. 10, the cleaning device 57 includes a housing 59 in which the cleaning brush 58 is stored. The base 23 is connected to a suction means (not shown) while being opened so as to be able to come into contact with 23. A cleaning blade 60 for cleaning the surface of the transfer drum 23 is provided on a housing 59 of the cleaning device 57.
Are mounted at the same positions as the first, second, and third jam sensors 50, 51, and 52 in the axial direction of the transfer drum. Further, the cleaning blade 60 includes
The width is substantially the same as the detection width of the jam sensors 50, 51, and 52, and is formed and arranged to be in line contact or surface contact with the surface of the transfer drum 23.

As the cleaning blade 60,
For example, as shown in FIG. 11, a blade made of a synthetic resin such as silicone rubber or polyethylene terephthalate is used.
The cleaning blade 60 is fixed to the substrate 62 by, for example, and arranged in a so-called wiper direction along the rotation direction of the transfer drum 23 via the substrate 62, for example. The cleaning blade 60 is
A part of the housing 59 of the cleaning device 57 may be formed into a blade, and the cleaning blade 60 may be arranged in a so-called doctor direction along the direction opposite to the rotation direction of the transfer drum 23.

The cleaning blade 60 is
As shown in FIG. 12, by forming the distal end portion 60a in a curved shape, the contact with the surface of the transfer drum 23 may be made uniform in the width direction.

In this embodiment, there are provided jam sensors 50, 51 and 52 for detecting a defective transfer state of the transfer material 24 with respect to the transfer drum 23, and a cleaning blade 60 for cleaning the surface of the transfer drum 23. Since the blade 60 is disposed at the same position as the detection position of the jam sensors 50, 51, 52 in the axial direction of the transfer drum 23, the cleaning blade 60 is moved to the jam sensors 50, 5, 5 in the axial direction of the transfer drum 23.
Due to the extremely simple configuration of disposing them at the same position as 1, 52, it is possible to prevent the surface of the transfer drum 23 from becoming cloudy.
Erroneous detection of the jam sensors 50, 51, 52 can be prevented.

The other configuration and operation are the same as those of the above-described embodiment, and the description thereof will be omitted.

Third Embodiment FIG. 13 shows a third embodiment of the present invention. The same parts as those in the above embodiment are denoted by the same reference numerals and described.
This embodiment includes a conveyance failure detection unit that detects a conveyance state of the transfer material with respect to the transfer material carrier, and a blade-like cleaning unit that cleans the surface of the transfer material carrier. The means is arranged at the same position as the conveyance failure detecting means in the axial direction of the transfer material carrier.

That is, in this embodiment, as shown in FIG. 13, a paper suction roll 43 for adsorbing the transfer material 24 to the surface of the transfer drum 23 is provided with a housing 70. When the roll 43 comes into contact with the surface of the transfer drum 23,
The cleaning blade 71 is attached to the surface of the transfer drum 3 in a direction opposite to the rotation direction of the transfer drum 23. Further, the housing 70 may be configured such that a bracket of the paper suction roll 43 and a part of the support mylar for guiding the transfer material are formed into a blade or a blade is attached thereto.

The other configurations and operations are the same as those of the above-described embodiment, and the description thereof will be omitted.

In the above-described embodiment, as a member for attaching the cleaning blade, a cleaning device or a paper suction roll that comes into contact with or separates from the surface of the transfer drum 23 originally provided in the image forming apparatus is used. Of course, a detachable mechanism may be provided on the surface of the drum 23.

Fourth Embodiment FIG. 15 shows a fourth embodiment of the present invention.
In this embodiment, transfer material detecting means for detecting the transfer state of the transfer material on the transfer material carrier or density detecting means for detecting the toner concentration on the transfer material carrier, and A cleaning means for cleaning the transfer material carrier provided at least at the same position as the transfer material detection means or the density detection means is provided, and the axial length of the cleaning means is wider than the beam spot diameter of the detection means. The cleaning unit is configured to be narrower than the width, and is configured to be able to contact and separate from the transfer material carrier.

That is, in this embodiment, as shown in FIG.
3, a pre-adsorption sensor 50 for detecting whether or not the transfer material 24 is adsorbed on the surface of the transfer drum 23, and a transfer to a downstream side of a nip portion between the photosensitive drum 20 and the transfer member 24. A post-transfer sensor 51 for detecting whether or not the material 24 is held on the surface of the transfer drum 23 without moving to the photosensitive drum 20 side, and a transfer material at a position corresponding to the downstream side of the peeling device 44. A pre-cleaning sensor 52 for detecting whether or not 24 has been separated from the surface of the transfer drum 23 is provided. The sensors 50, 51, and 52 before and after the adsorption and after the transfer, for example, have a diameter of 3 mm toward the surface of the transfer drum 23.
By irradiating spot light of the degree, and detecting diffuse reflection light, specular reflection light, and the like from the surface side of the transfer drum 23, it is determined whether or not the transfer material 24 is optically held on the surface of the transfer drum 23. Is used. In addition, the sensor 5 before adsorption, after transfer, and before cleaning 5
As shown in FIG. 16, 0, 51, and 52 are all located at the same position along the axial direction of the transfer drum 23 and near one end of the effective image width.

In this embodiment, as shown in FIG. 15, the first cleaning device 57 has a housing 59 in which a cleaning brush 58 is housed.
Are opened so as to be able to contact the transfer drum 23, and are swingable about the fulcrum 80 in a direction in which the cleaning brush 58 comes into contact with and separates from the transfer drum 23. Further, a cleaning blade 60 as a second cleaning means for cleaning the surface of the transfer drum 23 is provided on the housing 59 of the cleaning device 57 before and after the transfer in the axial direction of the transfer drum 23, after transfer, and before cleaning sensors 50 and 51. , 52 are mounted at the same position as the transfer drum 23 in cooperation with the housing 59 of the cleaning device 57.
Can be separated from the surface. In addition, the cleaning blade 60 is disposed upstream of the cleaning brush 58. In addition, the cleaning blade 6
The axial length of 0 is set wider than the beam spot diameter of the sensors 50, 51, and 52 and smaller than the effective image width, and is formed so as to be in line contact or surface contact with the surface of the transfer drum 23. Is done. In this case, a support member facing the cleaning blade 60 may be provided on the inner surface side of the transfer drum 23 according to the axial length of the cleaning blade 60. In such a case, even if the length of the cleaning blade 60 in the axial direction is long to some extent, the transfer film 42 can be prevented from being deformed, and the surface of the transfer film 42 can be reliably cleaned over a predetermined length. can do.

The cleaning blade 60 includes:
For example, as shown in FIG. 17, a blade made of a synthetic resin such as silicon rubber or polyethylene terephthalate is used. The cleaning blade 60 is attached to a metal plate 62 constituting a housing 59 of a cleaning device 57 or to the housing 59. Metal plate 62
The cleaning blade 60 is fixed by an adhesive 61 and arranged in a so-called wiper direction along a rotation direction of the transfer drum 23 via a metal plate 62, for example. The cleaning blade 60 is
A part of the housing 59 of the cleaning device 57 may be formed into a blade, and the cleaning blade 60 may be arranged in a so-called doctor direction along the direction opposite to the rotation direction of the transfer drum 23. The contact pressure of the cleaning blade 60 on the surface of the transfer drum 23 is set to about 50 gf to about 500 gf, for example, about 200 gf.

Next, as shown in FIG. 15, the present inventors changed the length of the cleaning blade 60 in the axial direction under the condition that the opposing member sandwiching the transfer film 42 of the transfer drum 23 does not exist. In this case, an experiment was performed to confirm how the cleaning efficiency of the surface of the transfer drum 23 changes. The sensor 50 used had a beam spot diameter of 3 mm.

FIG. 18 shows the results of the above experiment.

As is clear from this figure, when the length of the cleaning blade 60 is 4 mm or more, the cleaning efficiency is 100%. When the length of the cleaning blade 60 is 20 mm, the cleaning efficiency is slightly reduced but 90%. As described above, it was found that the length of the cleaning blade 60 should be 4 mm or more and 20 mm or less.

As described above, in the above embodiment, the sensor 5 for detecting the transfer state of the transfer material 24 on the transfer drum 23 is used.
0, 51, 52, and a cleaning blade 60 for cleaning the surface of the transfer drum 23. The cleaning blade 60 is positioned at the same position as the detection position of the sensors 50, 51, 52 in the axial direction of the transfer drum 23. Since the cleaning blade 60 is disposed,
With the extremely simple configuration of being disposed at the same position as the jam sensors 50, 51, and 52 in the axial direction, it is possible to prevent the surface of the transfer drum 23 from becoming cloudy and prevent the sensors 50, 51, and 52 from being erroneously detected. Becomes possible.

The axial length of the cleaning blade 60 is larger than the beam spot diameter of the sensors 50, 51, and 52 and smaller than the effective image width. Since the length corresponding to the spot diameter can be reliably cleaned and is configured to be narrower than the effective image width, the areas corresponding to the sensors 50, 51, and 52 can be effectively cleaned. Further, since the cleaning means can be brought into contact with and separated from the transfer material carrier, the toner image transferred onto the transfer material is not damaged.

Further, the cleaning blade 60
The cleaning blade 58 comes into contact with and separates from the transfer drum 23 together with the cleaning brush 58, so that it is possible to prevent the cleaning blade 60 from interfering with the transfer material 24 without using a special member.

The axial length of the cleaning blade 60 is set wider than the beam spot diameters of the sensors 50, 51 and 52 to 20 mm or less. The corresponding length can be reliably cleaned, and, as clarified in the experiments of the present inventors, it is possible to prevent the cleaning efficiency from being lowered as in the case where the length exceeds 20 mm. it can.

Further, the cleaning blade 60
Is disposed on the upstream side of the cleaning brush 58, so that the toner and external additives of the toner scraped off by the cleaning blade 60, and further the paper dust and the like are cleaned by the cleaning brush 58 located downstream. Can be.

The other configuration and operation are the same as those of the above-described embodiment, and the description thereof will be omitted.

Fifth Embodiment FIG. 19 shows a fifth embodiment of the present invention.
In this embodiment, transfer material detecting means for detecting the transfer state of the transfer material on the transfer material carrier or density detecting means for detecting the toner concentration on the transfer material carrier, and A cleaning means for cleaning the transfer material carrier provided at least at the same position as the transfer material detection means or the density detection means is provided so as to be able to contact and separate from the transfer material carrier, and the axial length of the cleaning means is as described above. It is configured to be wider than the beam spot diameter of the detecting means and narrower than the effective image width.

That is, in this embodiment, as shown in FIG. 19, the cleaning blade 60 is
The cleaning blade 60 is attached to at least one of the lower portion of the transfer drum 3 and the housing 70 of the transfer material suction assisting member.
3 can be brought into contact with and separated from the surface.

The length of the cleaning blade 60 in the axial direction is set to be wider than the beam spot diameter of the sensors 50, 51 and 52 and narrower than the effective image width.
The transfer drum 23 is formed and arranged to be in line contact or surface contact with the surface of the transfer drum 23. Note that the axial length of the cleaning blade 60 may be set wider than the beam spot diameter of the sensors 50, 51, and 52 to 20 mm or less.

As described above, the cleaning blade 6
No. 0 is configured so as to be brought into contact with and separated from members related to the feeding and separation of the transfer material 24 on the transfer drum 23, so that the cleaning blade 60 can be used without using any special member. It is possible to reliably prevent the upper transfer material 24 from being affected.

The other configuration and operation are the same as those of the above-described embodiment, and the description thereof will be omitted.

Sixth Embodiment FIG. 20 shows a sixth embodiment of the present invention.
In this embodiment, transfer material detecting means for detecting the transfer state of the transfer material on the transfer material carrier or density detecting means for detecting the toner density on the transfer material carrier, and contact with the surface of the transfer material carrier Transfer material peeling means for peeling off the transfer material from the transfer material carrier with the transfer material peeling means at the same position as the transfer material detecting means or the density detecting means in the axial direction of the transfer material carrier. Are arranged so as to make at least line contact with the surface of the transfer material carrier in the axial direction.

Further, in this embodiment, the transfer material peeling means is configured to contact the surface of the transfer material carrier in the entire circumferential direction of the transfer material carrier during the peeling operation.

That is, in this embodiment, as shown in FIG.
The peeling finger 53 comes into contact with the surface of the transfer drum 23 in the entire circumferential direction of the transfer drum 23 during the peeling operation, as shown in FIG. I have. During continuous copying in the monochrome mode, the peeling finger 53 remains in contact with the surface of the transfer drum 23.

With this configuration, the entire periphery of the transfer drum 23 can be cleaned, and the sensor 5
Even when the sensors 0, 51, and 52 are configured to perform static detection, that is, always detect the entire circumference of the transfer drum 23, it is possible to reliably prevent the sensors 50, 51, and 52 from being erroneously detected.

Further, the transfer drum 23
In some cases, a transfer drum as shown in FIG. 22 may be used in addition to the one shown in FIG. This transfer drum 2
3, ring members 40, 40 as a pair of annular members arranged at both ends in the axial direction, as shown in FIG.
A drum-shaped frame having a tie bar plate 41 as a connecting member for connecting these ring members 40, 40 is provided, and both side ends of a transfer film 42 made of a dielectric film such as polyvinylidene fluoride (PVdF) are provided. In a state wound around the frame along the outer peripheral surfaces of the ring members 40, 40, they are fixed by bonding with a double-sided tape or the like, and the circumferential leading end 42 a and the rear end 4 of the transfer film 42.
As shown in FIG. 23, 2a and 2a are bonded to each other with a double-sided tape 43 to form a hollow cylindrical shape. At this time, the adhesive portion of the transfer film 42 cannot transfer the toner image formed on the photosensitive drum 20 satisfactorily.
Is set in a non-image area of the transfer drum 23, that is, in a position corresponding to the tie bar plate 41, so as to be located on the tie bar plate 41 with a gap therebetween.

As described above, the double-sided tape 43 is used as the transfer drum 23 in a state where both ends of the transfer film 42 are overlapped with each other.
When a transfer finger is used, the separation finger is brought into contact with the surface of the transfer drum 23 in the entire circumferential direction of the transfer drum 23 during the separation operation, and
Of the sensor 50,
Static detection of 51 and 52 becomes possible.

When a transfer drum 23 as shown in FIG. 9 is used, as shown in FIG. 24, except for the tie bar plate 41 of the transfer drum 23,
The peeling finger 53 is brought into contact with the surface of the transfer drum 23 only in a detection area such as a sensor 50 for detecting the transport state of the transfer material 24 on the transfer drum 23 in the circumferential direction of the transfer drum 23 during the peeling operation. May be configured.

The other configuration and operation are the same as those of the above-described embodiment, and the description thereof will be omitted.

Seventh Embodiment FIG. 25 shows a seventh embodiment of the present invention.
In this embodiment, transfer material detecting means for detecting the transfer state of the transfer material on the transfer material carrier or concentration detecting means for detecting the toner concentration on the transfer material carrier, and transfer material on the surface of the transfer material carrier A transfer material adsorbing auxiliary member for adsorbing the transfer material, the transfer material adsorbing auxiliary member being located at least at the same position as the transfer material detecting means or the density detecting means in the axial direction of the transfer material supporting body. Are arranged so as to make at least a line contact with the surface in the axial direction of.

That is, in this embodiment, as shown in FIG. 25, the support mylar 8
5 is provided with a protrusion 86 at the front end of FIG.
When the projection 86 of the support mylar 85 of the transfer material suction assisting member comes into contact with the surface of the transfer drum 23 at the timing shown in FIG. During continuous copying in the monochrome mode, the peeling finger 53 remains in contact with the surface of the transfer drum 23.

The other configuration and operation are the same as those of the above-described embodiment, and the description thereof will be omitted.

Eighth Embodiment FIG. 27 shows an eighth embodiment of the present invention.
In this embodiment, the cleaning means is configured to be provided in a first inner cleaning means for cleaning the transfer material carrier.

That is, in this embodiment, the cleaning blade 60 is opposed to the cleaning brush.
The cleaning blade 60 is attached to an inner cleaning brush 87 provided inside the transfer drum 23.
7 and comes into contact with the inner surface of the transfer drum 23 at a predetermined timing. The cleaning blade 60 may be arranged upstream of the inner cleaning brush 87.

The other configuration and operation are the same as those of the above-described embodiment, and the description thereof will be omitted.

Ninth Embodiment FIG. 28 shows a ninth embodiment of the present invention.
In this embodiment, the transfer material detecting means for detecting the transfer state of the transfer material on the transfer material support or the density detecting means for detecting the toner density on the transfer material support is in contact with the inner surface of the transfer material support. And an inner peeling means for peeling the transfer material from the transfer material carrier.The inner peeling means is provided at least at the same position as the transfer material detecting means or the density detecting means in the axial direction of the transfer material carrier. The transfer material carrier is arranged so as to make at least line contact with the surface in the axial direction of the transfer material carrier.

That is, in this embodiment, as shown in FIG. 28, a peeling inner pressing member 54 as an inner peeling means is disposed inside the transfer drum 23. At the same position as 51 and 52, the transfer drum 23 is in line contact with the inner surface in the axial direction. For this reason, as shown in FIG. 28B, the distal end of the peeling inner pressing member 54 is formed in an edge shape.

The other constructions and operations are the same as those of the above-described embodiment, and the description thereof will be omitted.

Tenth Embodiment FIG. 29 shows a tenth embodiment of the present invention. The same parts as those of the above embodiment are denoted by the same reference numerals. In this embodiment, the cleaning means The transfer member is provided on the transfer assisting member, and is configured to be a means for cleaning the inner surface of the transfer material carrier during the transfer operation.

That is, in this embodiment, the transfer corotron 25 disposed at the transfer position inside the transfer drum has the transfer guide 90 made of a Mylar film or the like for concentrating the transfer electric field at the transfer position. The cleaning blade 60 is attached to the transfer guide 90. The transfer guide 90 comes in contact with and separates from the inner surface of the transfer drum 23 at a predetermined timing.

The other configuration and operation are the same as those of the above-described embodiment, and the description thereof will be omitted.

Eleventh Embodiment FIG. 30 shows an eleventh embodiment of the present invention. The same parts as those of the above embodiment are denoted by the same reference numerals. It is configured to be disposed on the transfer material suction assisting member.

That is, in this embodiment, the transfer drum 2
3 is provided with a suction guide 91 made of a mylar film or the like for concentrating the suction electric field at the suction position, and the cleaning guide 60 is attached to the suction guide 91. Is installed. The suction guide 19 may be configured to contact or separate from the inner surface of the transfer drum 23 at a predetermined timing, or may be configured to always contact the inner surface of the transfer drum 23.

The other constructions and operations are the same as those of the above-described embodiment, and a description thereof will be omitted.

In the above embodiment, the case where the cleaning means comprises a blade as shown in FIG. 11 has been described. However, the cleaning means comprises a web cleaning 92 as shown in FIG.
A brush cleaning 93 as shown in FIG. 2 may be used. However, also in this case, the width of the web or the brush is set to be larger than the beam spot diameter of the sensor.

In the above-described embodiment, the case where one cleaning means is provided along the axial direction of the transfer drum has been described. However, if necessary, a plurality of cleaning means may be provided along the axial direction of the transfer drum. You may.

[0112]

According to the present invention, in the image forming apparatus according to the first aspect, a transfer material detecting means for detecting a transfer state of the transfer material on the transfer material carrier. Alternatively, a density detecting means for detecting a toner density on the transfer material carrier, and a transfer material carrier provided at least at the same position as the transfer material detector or the density detector in the axial direction of the transfer material carrier is cleaned. A cleaning unit is provided, and the axial length of the cleaning unit is configured to be wider than the beam spot diameter of the detection unit and narrower than the effective image width, and the cleaning unit contacts and separates from the transfer material carrier. The cleaning means is at least the same as the transfer material detecting means or the density detecting means in the axial direction of the transfer material carrier. By an extremely simple structure of arranging the location, it can prevent clouding of the surface of the transfer material carrying member,
It is possible to prevent erroneous detection of the transfer material detecting means or the density detecting means.

The length of the cleaning means in the axial direction is wider than the beam spot diameter of the detection means and narrower than the effective image width. Since the cleaning can be surely performed and is configured to be narrower than the effective image width, the area corresponding to the detecting unit can be effectively cleaned. Further, since the cleaning means can be brought into contact with and separated from the transfer material carrier, the toner image transferred onto the transfer material is not damaged.

Further, the image forming apparatus according to the second aspect of the present invention detects a transfer material detecting means for detecting a transfer state of the transfer material on the transfer material carrier or a toner concentration on the transfer material carrier. A density detecting means, and a cleaning means for cleaning a transfer material carrier provided at least at the same position as the transfer material detecting means or the density detecting means in the axial direction of the transfer material carrier; The length is wider than the beam spot diameter of the detecting means and is equal to or less than 20 mm, and the cleaning means is configured to be able to contact and separate from the transfer material carrier. The length corresponding to the beam spot diameter can be reliably cleaned, and, as has been clarified in the experiments of the present inventors, the length is equal to the beam spot diameter. With a cleaning efficiency can be prevented from decreasing as in the case of over 0 mm, it is possible to create a cleaning means compact, there is a merit in terms of cost.

Further, in the image forming apparatus according to the third aspect of the present invention, the first cleaning means for cleaning the transfer material carrier over the effective image width, and the transfer state of the transfer material on the transfer material carrier And a density detecting means for detecting the toner density on the transfer material carrier, and at least at the same position as the transfer material detecting means or the density detecting means in the axial direction of the transfer material carrier. A second cleaning means for cleaning the transfer material carrier is provided so as to be capable of coming into contact with and separating from the transfer material carrier, and the axial length of the cleaning means is wider than the beam spot diameter of the detection means and is greater than the effective image width. And the second cleaning means is provided with the first cleaning means.
Is arranged on the upstream side of the cleaning means, so that the same action and effect as those of the first aspect of the invention can be obtained, and of course, it is removed by the second cleaning means. Toner, external additives, paper powder, and the like can be cleaned by the first cleaning means located downstream.

Further, in the image forming apparatus according to a fourth aspect of the present invention, the first cleaning means for cleaning the transfer material carrier over the effective image width, and the conveyance of the transfer material on the transfer material carrier A transfer material detecting means for detecting a state or a density detecting means for detecting a toner concentration on the transfer material carrier, and a transfer material detecting means or a density detecting means provided at least at the same position in the axial direction of the transfer material carrier; A second cleaning means for cleaning the transfer material carrier is provided so as to be able to come into contact with and separate from the transfer material carrier, and the axial length of the cleaning means is wider than the beam spot diameter of the detection means to 20 mm or less. The second cleaning unit is configured to be disposed upstream of the first cleaning unit. Has both the action and effects of the invention described in the item 2 according to claim 3 wherein.

Further, in the image forming apparatus according to a fifth aspect of the present invention, a transfer material detecting means for detecting a transfer state of the transfer material on the transfer material support or a toner concentration on the transfer material support is detected. A density detecting means and a cleaning means for cleaning a transfer material carrier provided at least at the same position as the transfer material detection means or the density detection means in the axial direction of the transfer material carrier are brought into contact with the transfer material carrier. The cleaning unit is configured so that the length in the axial direction of the cleaning unit is wider than the beam spot diameter of the detection unit and narrower than the effective image width, and the cleaning unit supplies the transfer material on the transfer material carrier. Since it is configured to contact and separate with members related to feeding and peeling, in the invention according to claim 1, the cleaning means can be used without using a special member. From hinder the transfer material on Utsushizai carrier can be reliably prevented.

The image forming apparatus according to claim 6 of the present invention detects a transfer material detecting means for detecting a transfer state of the transfer material on the transfer material carrier or a toner concentration on the transfer material carrier. A density detecting means and a cleaning means for cleaning a transfer material carrier provided at least at the same position as the transfer material detection means or the density detection means in the axial direction of the transfer material carrier are brought into contact with the transfer material carrier. The cleaning unit is configured so that the length of the cleaning unit in the axial direction is wider than the beam spot diameter of the detection unit and is equal to or less than 20 mm, and the cleaning unit feeds and separates the transfer material on the transfer material carrier. Since it is configured so as to contact and separate in conjunction with the members related to (1), it has both the functions and effects of the inventions described in claims (2) and (5).

Further, in the image forming apparatus according to a tenth aspect of the present invention, a transfer material detecting means for detecting a transfer state of the transfer material on the transfer material support or a toner concentration on the transfer material support is detected. A density detecting unit, and a transfer material peeling unit that comes into contact with the surface of the transfer material carrier to peel off the transfer material from the transfer material carrier. The transfer material peeling unit is provided in the axial direction of the transfer material carrier. At least at the same position as the transfer material detecting means or the density detecting means in the above, so as to at least linearly contact the surface in the axial direction of the transfer material supporting body, without adding a new member, The surface of the transfer material carrier is externally added to the toner by scraping off the external additive of the toner or fine particles such as paper powder attached to the surface of the transfer material carrier by the transfer material peeling means that is in linear contact with the surface of the toner. And paper powder Thus it is possible to prevent the white turbidity, it is possible to prevent erroneous detection of the transfer material detecting means or the concentration-detecting means.

According to a thirteenth aspect of the present invention, there is provided an image forming apparatus, wherein a transfer material detecting means for detecting a transfer state of the transfer material on the transfer material carrier or a toner concentration on the transfer material carrier. A density detection unit, and a transfer material adsorption auxiliary member for adsorbing the transfer material on the surface of the transfer material support, wherein the transfer material adsorption auxiliary member is a transfer material detection unit in the axial direction of the transfer material support or Since the transfer material carrier is arranged at least at the same position as the density detecting means so as to make at least line contact with the surface in the axial direction of the transfer material carrier, the same operation and effect as those of the tenth aspect are obtained.

Further, according to the image forming apparatus of the present invention, there is provided a transfer material detecting means for detecting a transfer state of the transfer material on the transfer material carrier or a toner concentration on the transfer material carrier. Density detecting means, and an inner peeling means that comes into contact with the inner surface of the transfer material carrier to peel off the transfer material from the transfer material carrier. The inner peeling means is provided in the axial direction of the transfer material carrier. 11. The same operation as the invention according to claim 10, since the transfer material carrier is arranged at least at the same position as the transfer material detection means or the density detection means so as to make at least line contact with the surface in the axial direction of the transfer material carrier. -Has an effect.

[Brief description of the drawings]

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

FIG. 2 is a perspective view showing a positional relationship between a peeling finger and a jam sensor.

FIG. 3 is a perspective view showing a peeling finger.

FIG. 4 is a plan view showing a distal end portion of a peeling finger.

FIG. 5 is a front view showing a positional relationship between a peeling finger and a jam sensor.

FIG. 6 is a cross-sectional configuration diagram showing a distal end portion of a peeling finger.

FIG. 7 is a perspective view showing a peeling finger.

FIG. 8 is a configuration diagram showing an embodiment of an image forming apparatus according to the present invention.

FIG. 9 is a perspective view showing a transfer drum.

FIG. 10 is a main part configuration diagram showing Embodiment 2 of the image forming apparatus according to the present invention.

FIG. 11 is a perspective view showing a cleaning blade.

FIG. 12 is a perspective view showing a modification of the cleaning blade.

FIGS. 13A and 13B are main part configuration diagrams showing an image forming apparatus according to a third embodiment of the present invention.

FIG. 14 is a configuration diagram illustrating an image forming unit of a conventional image forming apparatus.

FIG. 15 is a configuration diagram illustrating a main part of an image forming apparatus according to a fourth embodiment of the present invention.

FIG. 16 is a configuration diagram showing an arrangement of sensors.

FIG. 17 is a perspective view showing a cleaning blade.

FIG. 18 is a graph showing experimental results.

FIG. 19 is a configuration diagram showing a main part of an image forming apparatus according to Embodiment 5 of the present invention.

FIG. 20 is a configuration diagram showing a main part of an image forming apparatus according to Embodiment 6 of the present invention.

FIG. 21 is a timing chart showing the contact timing of the peeling finger.

FIG. 22 is a perspective view showing another embodiment of the transfer drum.

FIG. 23 is a sectional view showing a connection portion of the transfer drum.

FIG. 24 is an explanatory diagram showing the contact timing of the peeling finger.

FIGS. 25A and 25B show Embodiment 7 of the present invention.
1A and 1B are a configuration diagram showing a main part of an image forming apparatus according to the first embodiment and an enlarged view of the main part.

FIG. 26 is a timing chart showing the contact timing of the suction assisting member.

FIG. 27 is a configuration diagram showing a main part of an image forming apparatus according to Embodiment 8 of the present invention.

FIGS. 28 (a) and (b) show a ninth embodiment of the present invention.
1A and 1B are a configuration diagram showing a main part of an image forming apparatus according to the first embodiment and an enlarged view of the main part.

FIG. 29 is a configuration diagram showing a main part of an image forming apparatus according to Embodiment 10 of the present invention.

FIG. 30 is a configuration diagram showing a main part of an image forming apparatus according to Embodiment 11 of the present invention.

FIG. 31 is a configuration diagram showing another embodiment of the cleaning means.

FIG. 32 is a configuration diagram showing another embodiment of the cleaning means.

[Explanation of symbols]

23 transfer drum, 24 transfer material, 50, 51, 52
Jam sensor, 53 peel finger.

Continuing from the front page (72) Inventor Masaaki Tokunaga 2274 Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Corporation (72) Inventor Ryoichi Tsuruoka 2274 Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Corporation (56) References Special JP-A-6-195011 (JP, A) JP-A-5-61369 (JP, A) JP-A-7-36226 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15 / 16 G03G 15/01 G03G 15/14 G03G 21/10

Claims (14)

(57) [Claims] A plurality of toner images having different colors are sequentially formed on an image carrier, and the plurality of toner images formed on the image carrier are transferred onto a transfer material carried on a transfer material carrier. In an image forming apparatus for forming an image by transferring images in a state of being sequentially superimposed, a transfer material detecting means for detecting a transfer state of the transfer material on the transfer material carrier or a toner concentration on the transfer material carrier is detected. A density detecting means, and a cleaning means for cleaning a transfer material carrier provided at least at the same position as the transfer material detecting means or the density detecting means in the axial direction of the transfer material carrier; The length is configured to be wider than the beam spot diameter of the detecting means and narrower than the effective image width, and the cleaning means is capable of coming into contact with and separating from the transfer material carrier. An image forming apparatus comprising. 2. A method according to claim 1, wherein a plurality of toner images having different colors are sequentially formed on the image carrier, and the plurality of toner images formed on the image carrier are transferred onto a transfer material carried on the transfer material carrier. In an image forming apparatus for forming an image by transferring images in a state of being sequentially superimposed, a transfer material detecting means for detecting a transfer state of the transfer material on the transfer material carrier or a toner concentration on the transfer material carrier is detected. A density detecting means, and a cleaning means for cleaning a transfer material carrier provided at least at the same position as the transfer material detecting means or the density detecting means in the axial direction of the transfer material carrier; The length is wider than the beam spot diameter of the detection means.
The image forming apparatus is configured to have a length of 0 mm or less, and the cleaning unit can be brought into contact with and separated from the transfer material carrier. 3. A plurality of toner images of different colors are sequentially formed on an image carrier, and the plurality of toner images formed on the image carrier are transferred onto a transfer material carried on a transfer material carrier. In an image forming apparatus for forming an image by transferring images in a sequentially superposed state, a first cleaning unit for cleaning the transfer material carrier over an effective image width, and a transfer state of the transfer material on the transfer material carrier And a density detecting means for detecting the toner density on the transfer material carrier, and at least at the same position as the transfer material detecting means or the density detecting means in the axial direction of the transfer material carrier. A second cleaning means for cleaning the transfer material carrier is provided so as to be able to come into contact with and separate from the transfer material carrier, and the axial length of the cleaning means is equal to the beam spot of the detection means. Together are configured narrower than the wider the effective image width than the second cleaning means, the image forming apparatus characterized by being arranged on an upstream side of said first cleaning unit. 4. A plurality of toner images of different colors are sequentially formed on an image carrier, and the plurality of toner images formed on the image carrier are transferred onto a transfer material carried on a transfer material carrier. In an image forming apparatus for forming an image by transferring images in a state of being sequentially superimposed, a first cleaning unit for cleaning the transfer material carrier over an effective image width, and a transfer state of the transfer material on the transfer material carrier And a density detecting means for detecting the toner density on the transfer material carrier, and at least at the same position as the transfer material detecting means or the density detecting means in the axial direction of the transfer material carrier. A second cleaning means for cleaning the transfer material carrier is provided so as to be able to come into contact with and separate from the transfer material carrier, and the axial length of the cleaning means is equal to the beam spot of the detection means. Together are configured in wide 20mm or less than, the second cleaning means, the image forming apparatus characterized by being arranged on an upstream side of said first cleaning unit. 5. A method for forming a plurality of toner images having different colors on an image carrier in succession, and applying the plurality of toner images formed on the image carrier to a transfer material carried on a transfer material carrier. In an image forming apparatus for forming an image by transferring images in a state of being sequentially superimposed, a transfer material detecting means for detecting a transfer state of the transfer material on the transfer material carrier or a toner concentration on the transfer material carrier is detected. A density detecting means and a cleaning means for cleaning a transfer material carrier provided at least at the same position as the transfer material detection means or the density detection means in the axial direction of the transfer material carrier are brought into contact with the transfer material carrier. The cleaning unit is configured so that the length in the axial direction of the cleaning unit is wider than the beam spot diameter of the detection unit and narrower than the effective image width, and the cleaning unit includes the transfer material carrier. Feeding and image forming apparatus characterized by and away in conjunction with the members related to the separation of the transfer material. 6. A plurality of toner images of different colors are sequentially formed on an image carrier, and the plurality of toner images formed on the image carrier are transferred onto a transfer material carried on a transfer material carrier. In an image forming apparatus for forming an image by transferring images in a state of being sequentially superimposed, a transfer material detecting means for detecting a transfer state of the transfer material on the transfer material carrier or a toner concentration on the transfer material carrier is detected. A density detecting means and a cleaning means for cleaning a transfer material carrier provided at least at the same position as the transfer material detection means or the density detection means in the axial direction of the transfer material carrier are brought into contact with the transfer material carrier. The cleaning unit is configured so that the length in the axial direction of the cleaning unit is wider than the beam spot diameter of the detection unit and is equal to or less than 20 mm. An image forming apparatus characterized by and away feed and in conjunction with the members related to the release of wood. 7. The cleaning means or the second cleaning means .
The image according to any one of claims 1 to 6, wherein the rinsing means is provided on the transfer assisting member, and is means for cleaning the inner surface of the transfer material carrier during the transfer operation. Forming equipment. 8. The cleaning means or the second cleaning means .
7. The image forming apparatus according to claim 1, wherein the rinsing means is provided on the transfer material suction assisting member. 9. The cleaning unit or the second cleaning unit .
7. The image forming apparatus according to claim 1, wherein the rinsing means is provided in the first inner cleaning means for cleaning the transfer material carrier. 10. A plurality of toner images of different colors are sequentially formed on an image carrier, and the plurality of toner images formed on the image carrier are transferred onto a transfer material carried on a transfer material carrier. In an image forming apparatus for forming an image by transferring images in a state of being sequentially superimposed, a transfer material detecting means for detecting a transfer state of the transfer material on the transfer material carrier or a toner concentration on the transfer material carrier is detected. A density detecting unit, and a transfer material peeling unit that comes into contact with the surface of the transfer material carrier to peel off the transfer material from the transfer material carrier. The transfer material peeling unit is provided in the axial direction of the transfer material carrier. An image forming apparatus, which is arranged at least at the same position as the transfer material detecting means or the density detecting means so as to make at least line contact with the surface of the transfer material carrier in the axial direction. 11. The image forming apparatus according to claim 10, wherein the transfer material peeling unit contacts the surface of the transfer material carrier in the entire circumferential direction of the transfer material carrier during the peeling operation. 12. The transfer material detecting means or transfer material detecting means for detecting the transfer state of the transfer material on the transfer material support in the circumferential direction of the transfer material support during the peeling operation. 11. The image forming apparatus according to claim 10, wherein only the detection area of the density detection unit for detecting the toner density contacts the surface of the transfer material carrier. 13. A plurality of toner images of different colors are sequentially formed on an image carrier, and the plurality of toner images formed on the image carrier are transferred onto a transfer material carried on a transfer material carrier. In an image forming apparatus for forming an image by transferring images in a state of being sequentially superimposed, a transfer material detecting means for detecting a transfer state of the transfer material on the transfer material carrier or a toner concentration on the transfer material carrier is detected. A density detection unit, and a transfer material adsorption auxiliary member for adsorbing the transfer material on the surface of the transfer material support, wherein the transfer material adsorption auxiliary member is a transfer material detection unit in the axial direction of the transfer material support or An image forming apparatus, wherein at least the same position as the density detecting means is arranged so as to make at least line contact with the surface in the axial direction of the transfer material carrier. 14. A plurality of toner images having different colors sequentially formed on an image carrier, and the plurality of toner images formed on the image carrier are transferred onto a transfer material carried on a transfer material carrier. In an image forming apparatus for forming an image by transferring images in a state of being sequentially superimposed, a transfer material detecting means for detecting a transfer state of the transfer material on the transfer material carrier or a toner concentration on the transfer material carrier is detected. A density detecting unit, and an inner peeling unit that comes into contact with the inner surface of the transfer material carrier to peel off the transfer material from the transfer material carrier. An image forming apparatus, wherein the image forming apparatus is arranged at least at the same position as the material detecting means or the density detecting means so as to make at least line contact with the surface of the transfer material carrier in the axial direction.