JPH11194690A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively lengthen the lives of the cleaning blades or photoreceptor drums of all image-forming units without requiring a complex structure and without impairing coloring properties of toner, in an image forming device. SOLUTION: A toner pattern formed on the photoreceptor by the image- forming unit using toner whose color is the most satisfactory for the abrasiveness of the photoreceptors 1 or cleaning blades 51 is transferred to a transfer belt 6. Further, the toner is carried to the other image-forming units, and reversely transferred to the photoreceptors 1 of the image forming units. Thus, the toner which is satisfactory for the abrasiveness of the cleaning blades 51 are supplied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine and a printer, and more particularly to improvement of wear of an image carrier and a cleaning blade of an apparatus having a plurality of image forming units.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a four-color full-color copying machine provided with a plurality of image forming units, in order to make the developability of the toner of each color proper and the like, each of the individual colors is separated. Processing conditions are often applied. Therefore, the abrasion of the cleaning blade or the abrasion of the photosensitive drum that cleans the toner remaining on the photosensitive drum serving as the image carrier differs for each image forming unit, and the PM (Preventive Maintenance; failure prevention maintenance) of the unit is different. ) The replacement cycle was tailored to the shortest unit.
In addition, the life of these consumables has been improved by adding a cleaning aid to the toner to increase the abrasion of the cleaning blade or the photosensitive drum.

[0003]

However, usually,
In a full-color developer, a cleaning aid cannot be added so much due to a problem of color development. Therefore, there is a limit in extending the life of the consumable.

Further, the present applicant previously provided a means for supplying a cleaning aid around a transfer belt in a so-called tandem type image forming apparatus having a plurality of image forming units, and provided a means for supplying a cleaning aid via the transfer belt. However, it is necessary to provide a cleaning aid supply unit specially, and there is a problem that the configuration becomes complicated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a toner of a color whose coloring property is not so problematic contains a large amount of a cleaning aid which does not easily wear the image carrier and the cleaning blade. It is noted that the cleaning blades of all image forming units can be effectively removed without requiring a complicated configuration such as providing a special cleaning aid supply unit, and without impairing the color developing properties of the toner. It is an object of the present invention to provide an image forming apparatus capable of extending the life of a photosensitive drum.

[0006]

In order to achieve the above object, the present invention provides an image carrier, a latent image forming means for forming an electrostatic latent image on the image carrier, and Developing means for adhering toner to the latent image to form a toner image; transfer means for conveying the transferred member and transferring the toner image to the transferred member; and cleaning for cleaning the toner remaining on the image carrier In an image forming apparatus in which a plurality of image forming units each including a cleaning unit having a blade are arranged along a transfer unit, an image forming unit using a toner of a color having the best abrasion of the image carrier or the cleaning blade is used. Transferring the toner pattern formed on the image bearing member to the transfer means, transferring the toner pattern to another image forming unit by the transfer means, and forming the image from the transfer means. By reverse transcription the image carrier knit, in which so as to provide a good toner of abrasion to the cleaning unit.

In the above arrangement, one image forming apparatus uses a toner of a color having the best abrasion of the image carrier or the cleaning blade, that is, a toner having a characteristic of least abrading the image carrier or the cleaning blade. Since the toner can be supplied from the unit to the cleaning blade of another image forming unit by transfer and conveyance by the transfer unit and reverse transfer, the wear of the image carrier and the cleaning blade of the other image forming unit is also improved. be able to. The color toner with good abrasion supplied from the other unit is blocked by the edge of the cleaning blade, but is gradually consumed with the normal image forming operation. Need to be done on a regular basis.

According to a second aspect of the present invention, in the configuration of the first aspect, a cleaning unit for cleaning the toner remaining on the transfer unit is provided, and the cleaning unit can be freely selected between a cleaning state and a non-cleaning state. Things. In this configuration, even if the image forming unit using the toner having the best abrasion of the image carrier and the cleaning blade is not located on the most upstream side in the transport direction of the transfer unit, the toner is removed from the unit. Can also be conveyed to the unit located on the upstream side by the transfer means, and can be reverse-transferred from the transfer means to the image carrier, so that the above-mentioned effect can be obtained.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of a four-color full-color image forming apparatus of a general tandem process. This image forming apparatus includes four image forming units 10, 20, 30, and 40 corresponding to full colors of four colors (cyan, magenta, yellow, and black).
Each of these image forming units includes a charging device 2 for uniformly charging the photoconductor 1 around the photoconductor 1 (image carrier), and an image formed on the photoconductor 1 to form an electrostatic latent image. Exposure unit 3 (latent image forming unit), developing device 4 (developing unit) for forming a toner image by attaching toner to the electrostatic latent image, and cleaning blade 51 for cleaning toner remaining on photoconductor 1 And a cleaning device 5 (cleaning means). These image forming units 10, 20, 30, and 40 are sequentially arranged along a transfer belt 6 (a part of a transfer unit) that conveys a transfer member such as transfer paper and transfers a toner image to the transfer member. ing.

Further, a transfer electrode 61 (transfer device) is provided on the opposite side of the photoreceptor 1 with the transfer belt 6 therebetween.
And a cleaning unit 5 to form a transfer unit. The transfer belt 6 is stretched between the transport rollers 65 and 66. Further, since the toner adhered to the transfer belt 6 causes stain on the back side of the transfer paper, the transfer paper is located downstream of the transfer belt 6 in the transport direction (left side in the figure) after the transfer paper is separated from the transfer belt 6. And a cleaning blade 7 for removing toner. The transfer belt 6 is made of a resin film belt made of PVDF (polyvinylidene fluoride), PC (polycarbonate), PET (polyethylene terephthalate) or ETFE (ethylene tetrafluoroethylene copolymer), or chloroprene rubber or urethane rubber. A semiconductor belt formed of a rubber belt as a material and having a self-static elimination property with a volume resistance of 10 ⁶ to 10 ¹² Ω · cm or an insulating belt of 10 ¹² to 10 ¹⁶ Ω · cm is used.

In the above configuration, a visual image of each color is formed on the photoreceptor 1 of each of the image forming units 10, 20, 30, and 40, and is developed by the developing device 4 with toner of each color. When the transfer paper conveyed on the transfer belt 6 passes through the transfer section of each image forming unit, the toner image is transferred onto the transfer paper. By repeating this operation in each image forming unit, a full-color image can be obtained on transfer paper.

FIG. 2 is a schematic diagram of an image forming apparatus according to the first embodiment. The basic configuration of this apparatus is the same as that shown in FIG. 1 described above, and an image using a toner of the color with the best abrasion of the photoconductor 1 or the cleaning blade 61 is provided as necessary or periodically. Each unit is controlled so that the toner is supplied from the forming unit to the cleaning means of all the other image forming units.

More specifically, the toner pattern formed on the photoreceptor 1 of the image forming unit using the toner having the best wear property is directly transferred to the transfer belt 6, and another image is formed by the transfer belt 6. The toner is conveyed to the unit and is reversely transferred from the transfer belt 6 to the photoreceptor 1, thereby supplying toner having good abrasion to the cleaning blade 51 of the cleaning device 5. This toner is blocked by the edge of the cleaning blade 51 and performs a lubricating function on the sliding surface with the photoconductor 1. as a result,
The abrasion of the photosensitive member 1 and the cleaning blade 51 of another image forming unit to which the toner has been supplied can be improved. Reverse transfer from the transfer belt 6 to the photoreceptor 1 can be performed by reversing the polarity with respect to normal transfer conditions.

At the downstream end of the transfer belt 6 in the transport direction,
A cleaning blade 7 is provided as a cleaning means for the transfer belt 6, and cleaning / non-cleaning of the transfer belt 6 is performed by controlling the pressing / releasing of the cleaning blade 7. With this configuration, even if the image forming unit that uses the toner of the color having the best abrasion property is not the one on the most upstream side in the transport direction of the transfer belt 6 (that is, the unit 20 instead of the unit 10). ,
30 or 40), the toner can be supplied to another upstream image forming unit via the transfer belt 6 in a state where the pressure contact of the cleaning blade 7 is released. The non-cleaning mode for cleaning the transfer belt 6 is not particularly required if the toner of the image forming unit 10 on the most upstream side is the toner having the best abrasion of the photoconductor 1 or the cleaning blade 51.

FIG. 3 is a schematic diagram of an image forming apparatus according to a second embodiment. The apparatus according to the present embodiment is different from the first embodiment in that a fur brush 7 ′ is used as a cleaning unit for the transfer belt 6. By controlling the polarity of the voltage applied to the fur brush 7 ', the cleaning / non-cleaning of the transfer belt 6 is switched. The cleaning / non-cleaning of the transfer belt 6 may be switched by pressing / releasing the fur brush 7 ′ itself.

FIG. 4 is a schematic diagram of an image forming apparatus according to the second embodiment. The apparatus of the present embodiment is different from the first embodiment in that an intermediate transfer system is employed. That is, a secondary transfer belt 8 is provided on the downstream side of the transfer belt 6 so as to face the transfer belt 6, and a transfer electrode 81 is provided on the opposite side of the transfer belt 8 from the transfer belt 6. 2
The next transfer belt 8 is stretched between the transport rollers 85 and 86. With this configuration, the transfer belt 6 is used as an intermediate transfer member, and the secondary transfer belt 8 is used for transporting transfer paper. The cleaning blade 7 is provided in the same manner as in the first embodiment, and performs cleaning / non-cleaning of the transfer belt 6 by controlling the pressing / releasing of the pressing.

FIG. 5 is a flowchart showing an example of the toner supply operation in the image forming apparatus according to each of the above embodiments.
This example is a case where the third image forming unit 30 counted from the upstream side in the transport direction of the transfer belt 6 is the toner having the best abrasion of the photoconductor 1 or the cleaning blade 51. The pattern formed on the transfer belt 6 is a solid or half pattern on the entire surface in the longitudinal direction of the photoconductor.

The above operation will be described. First, a pattern is formed by the third image forming unit 30 (# 1), transferred directly to the transfer belt 6 (# 2), and the pattern is conveyed by the transfer belt 6 (# 1). # 3). Here, first, the toner is conveyed to the fourth image forming unit 40 in order to supply the toner to the fourth image forming unit 40 (# 4). The transfer output is switched (# 5), and the photosensitive member 1 is rotated to supply toner to the cleaning blade 51 (# 6). Further, after the above operations # 1 to # 3, the toner is supplied to the first image forming unit 10 this time. Therefore, the transfer belt 6 is conveyed to the cleaning section (7, 7 ') (#
7), the cleaning of the transfer belt 6 is switched to the non-cleaning mode (# 8), and then the first image forming unit 1
0 (# 9), the transfer output of the first image forming unit 10 is switched for reverse transfer to the photoconductor 1 (# 10), and the photoconductor 1 is rotated to the cleaning blade 51. The toner is supplied (# 11). Finally, 2
To supply the toner to the second image forming unit 20,
The same operation as described above is performed (# 12 to # 16).

FIG. 6 is an explanatory diagram showing the timing at which the above-described toner supply operation starts. When the power is turned on by turning on the main switch (not shown),
And when the printing operation for a predetermined number of sheets is completed.
When the main switch is turned on (# 21), preliminary rotation of the process is performed (# 22), toner supply operation is started (# 23), and toner is supplied to the cleaning unit by rotation of the photoconductor (# 24). ), Stop the process (standby state) (# 25). When the printing (copying) operation for a predetermined number of sheets is completed (# 26), the same processing as the above-mentioned steps # 22 to # 24 is performed (# 27 to # 29), and the process proceeds to # 25.

The toner having the best abrasion of the photoreceptor 1 or the cleaning blade 51 may be, for example, a toner which is generated as a side effect due to a difference in post-processing conditions for each color. In order to improve the abrasion resistance of the toner, a cleaning aid added to the toner may be used. In the latter case, the cleaning aid is often added to a black toner in which the color developability is not a problem so as not to impair the color developability of the toner. Therefore,
In many cases, the black toner has the best abrasion. It is considered that the improvement in abrasion is attributed to the lubricating effect of the ultrafine particles for adjusting the charge amount and the flow amount contained in the toner.

It should be noted that the present invention is not limited to the configuration of the above embodiment, and various modifications are possible. For example, in the above-described embodiment, a case of four full colors has been described, but a mono color can be similarly applied.

[0022]

As described above, according to the image forming apparatus of the present invention, the toner is transferred from one image forming unit using a toner having good abrasion to the image carrier or the cleaning blade. Transfer and transport, and reverse transfer, to supply to the cleaning blade of another image forming unit, so that the life of the photoconductor or the cleaning blade is reliably improved with a simple configuration and without impairing the color developing properties. Can be done.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an image forming apparatus using a general tandem process as a premise of the present invention.

FIG. 2 is a schematic diagram of an image forming apparatus according to the first embodiment of the present invention.

FIG. 3 is a schematic diagram of an image forming apparatus according to a second embodiment of the present invention.

FIG. 4 is a schematic diagram of an image forming apparatus according to a third embodiment of the present invention.

FIG. 5 is a flowchart of an operation of the image forming apparatus.

FIG. 6 is a flowchart illustrating an operation of a toner supply timing of the image forming apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoconductor (image carrier) 2 charging device 3 image exposure unit 4 developing device (developing unit) 5 cleaning device (cleaning unit) 51 cleaning blade 6 transfer belt (transfer unit) 7 cleaning blade (transfer cleaning unit) 7 ′ fur Brush (transfer cleaning means) 8 Secondary transfer belt

Claims (2)

[Claims] An image carrier, a latent image forming means for forming an electrostatic latent image on the image carrier, a developing means for adhering toner to the electrostatic latent image to form a toner image; An image forming unit including a transfer unit that conveys the transfer member and transfers the toner image to the member to be transferred and a cleaning unit that has a cleaning blade that cleans the toner remaining on the image carrier is provided to the transfer unit. A plurality of image forming apparatuses arranged along the image transfer device, wherein a toner pattern formed on the image carrier by an image forming unit using a toner of a color having the best abrasion of the image carrier or the cleaning blade is transferred to the transfer unit. Further, this is conveyed to another image forming unit by the transfer means, and reversely transferred from the transfer means to the image carrier of the image forming unit, whereby An image forming apparatus comprising it has to supply a good toner of wear resistance to cleaning means. 2. The image forming apparatus according to claim 1, further comprising a cleaning unit for cleaning the toner remaining on the transfer unit, wherein the cleaning unit can be freely selected from a cleaning / non-cleaning state.