JPH07117889A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent foreign matter from being mixed into toner to be recovered for forming a high quality image without fogging and the like by mounting a means for charging a transfer material on the upstream side of a transfer material carrying means in a carrying direction. CONSTITUTION:A transfer material 25 which is carried from a paper feeding part 13 passes between guide plates 30, 31. During this process, the transfer material 25 is electrified with electric charge applied by the guide plate 31 on which a voltage applying part B is mounted. As a result, foreign matter on the transfer surface side of the transfer material 25 is electrified with negative electric charge. The transfer material 25 rushes between a pair of register rollers 14, and to a conductive layer of the surface of a register roller 14a, positive voltage is applied by a voltage applying part A, thereby allowing foreign matter such as paper powder which has adhered to the transfer material 25 to be attracted onto the roller 14a by electrostatic force which acts between the transfer material 25 and the roller 14a. The attracted foreign matter is carried to the position of a scraper 27 with the rotation of the roller 14a, which scrapes it off onto a recovery vessel 26 for its recovery. It is thus possible to ensure complete attraction of the foreign matter by electrostatic force, thereby forming a high quality image on the transfer material 25.

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, a facsimile and a printer, and more particularly to an image forming apparatus which reuses toner used for image formation.

[0002]

2. Description of the Related Art Conventional copying machines, facsimiles,
In an image forming apparatus such as a printer, foreign matter is generated from a transfer material when forming an image, which has many adverse effects on the formed image. The content of the generated foreign matter is, in particular, when the transfer material is paper, paper dust, an additive applied to the paper in the process of manufacturing the paper, or dust attached to the paper. These foreign matters are generated not only by mechanical stimuli received in the image forming apparatus when the paper is conveyed in the image forming apparatus, but also by the steps such as cutting in the manufacturing process of the paper, which causes the foreign matter on the paper at the time of manufacturing. Some are attached. The adverse effects of these foreign substances upon forming an image include the following (1) to (3). (1) The generated foreign matter adheres to the transport roller that transports the transfer material, thereby lowering the friction coefficient on the surface of the transport roller and deteriorating the paper transportability. (2) The above-mentioned foreign matter is a constituent element of the image forming apparatus, and particularly adheres to the electrodes of the charger disposed around the image carrier, the light receiving and emitting portions of the photosensor, and the like, thereby significantly deteriorating their performance. (3) When the residual toner after image formation is collected and reused, the above-mentioned foreign matter is mixed in the toner, so that fog or the like is generated during image formation and the image is deteriorated.

Therefore, image forming apparatuses having various foreign matter collecting functions have been conventionally proposed.

FIG. 6 is a schematic cross-sectional view of a foreign matter removing portion such as paper dust of an image forming apparatus which has been conventionally proposed. This conventional example will be described below.

The foreign matter removing unit shown in the figure is provided in the transfer material conveying path of the image forming apparatus. Guide plates 101, 102, 1 made of a metal plate such as iron fixedly provided in the image forming apparatus
The transfer material 105 is conveyed through the insides of the transfer materials 03 and 104.
Rollers 106 and 107 for transporting with 05 sandwiched are provided. The roller 106 is composed of a conductive metal roller, and the roller 106 has a voltage applying portion A ′.
Causes a voltage to be applied. A scraper 109 made of an elastic material is in contact with the surface of the roller 106, and the scraper 109 is fixed to a foreign matter collection container 110 fixed in the image forming apparatus.

Therefore, the transfer material 105 is the guide plates 101, 1
02, 103, 104 are conveyed in the direction of the arrow in the drawing, the rollers 106, 107 rotate in the direction of the arrow in the drawing, and when the transfer material 105 passes between the pair of rollers, foreign matter on the transfer material 105, for example, paper. The powder or the like is adsorbed to the roller 106. The dominant factor of this attracting force is that the foreign matter is caused by the rollers 106, 1.
The sheet is brought into a charged state or a polarized state by rubbing against a paper conveying roller or a guide plate in the image forming apparatus before passing through the interval 07. Therefore, between the foreign matter and the roller 106 to which a voltage is applied. This is because the electrostatic force works. Foreign matter such as paper dust adsorbed on the roller 106 is scraped by the scraper 109.
Thus, it is physically scraped from the roller 106 and collected in the collection container. After that, the transfer material 105 is conveyed to the photosensitive drum 111 that forms an image, and the toner image provided on the photosensitive drum 111 from a developing unit (not shown) is transferred by the transfer charger 114. After that, the transfer material 105 is separated from the photosensitive drum 111 by the separation charger 115 and conveyed. The toner remaining on the photosensitive drum without being transferred to the transfer material 105 is scraped off from the photosensitive drum 111 by the cleaning blade 112 and is then cleaned by the cleaner unit 113.
Will be collected. At this time, foreign matter such as paper dust that is not electrostatically attracted by the roller 106 and remains on the transfer material 105 is attracted to the photosensitive drum 111 by electrostatic force because the photosensitive drum 111 also has a potential on its surface. Like the toner remaining on the toner, the toner is scraped off by the cleaning blade 112 and collected by the cleaner unit 113.

The first purpose is to prevent foreign matter such as paper dust from being mixed into the toner collected in the cleaner section 113 and to use the collected toner again for image formation.

[0008]

However, in the image forming apparatus having the above-mentioned conventional foreign matter removing section,
Registration roller 106 for removing foreign matter by transfer material 105
After passing through the transfer material 105, the transfer material 105 transfers the toner image to the transfer material 105.
An electric charge is given by a transfer charger 114 that transfers the image to the.
As a result, foreign matter such as paper dust on the transfer material 105 is also charged, and the foreign matter has a larger electrostatic attraction force with respect to the photosensitive drum 111 than the electrostatic attraction force with respect to the resist roller 106. There is generated a foreign substance which is not adsorbed on the photosensitive drum 111 and is conveyed to the photosensitive drum 111 together with the transfer material 105 and adsorbed on the photosensitive drum 111 and collected by the cleaner 113. Therefore, when the collected toner is reused for image formation, fogging or the like occurs in the image due to the inclusion of foreign matter such as paper dust, thus deteriorating the performance of the image forming apparatus. Further, the position of the foreign matter removing means for preventing foreign matter from being mixed into the collected toner is indispensably upstream of the position of the photosensitive drum 111 in the transfer material transport path in the transfer material transport direction, and the foreign material was removed from the transfer material 105. In order to further reduce the possibility that foreign matter will adhere to the transfer material 105 later, it is desirable that the position be as close to the photosensitive drum 111 as possible. However, it is difficult to arrange a large-scale foreign matter removing means around the photosensitive drum 111 in a normal image forming apparatus because members such as a developing device, a transfer charging device, and a transfer material conveying path are mounted at high density. It was

The present invention has been made in order to solve the above-mentioned problems of the prior art. The purpose of the present invention is to prevent foreign matter from being mixed into the collected toner and to obtain a high-quality image without fog. An object of the present invention is to provide an image forming apparatus having a foreign matter removing unit.

[0010]

In order to achieve the above object, in the present invention, a conveying means for conveying a transfer material, a foreign matter removing means attached to the conveying means, and the conveying means are provided. A voltage applying means for applying a voltage, an image carrier,
Collecting means for collecting the toner remaining on the image carrier,
In the image forming apparatus having the above, the charging means for charging the transfer material is provided on the upstream side of the carrying means in the carrying direction.

The charging means is a guiding means for guiding the transfer material, and is preferably connected to a second voltage applying means for applying a voltage.

The charging means may be a corona charger.

The charging means may be a charging roller.

The charging means may be a brush charger composed of a conductive brush.

The conveying means is a roller, and the scraper is preferably brought into contact with the roller substantially parallel thereto.

A container may be provided at an end of the scraper that is not in contact with the roller, substantially parallel to the scraper.

[0017]

In the image forming apparatus constructed as described above, the charging means for charging the transfer material is provided on the upstream side of the carrying means in the carrying direction. Therefore, when the transfer material passes through the position facing the charging means, the transfer material is transferred. The foreign material on the material and the transfer material is charged and charged.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to illustrated embodiments.

In this embodiment, the present invention is applied to a copying machine. FIG. 1 is a sectional view showing the overall configuration of the image forming apparatus of this embodiment.

The configuration and operation of the image forming apparatus of this embodiment will be described with reference to FIG. A document placed on a document table is scanned and exposed, and a toner image is formed on this image on a sheet-shaped transfer material conveyed from a paper feeding table, and the image is discharged to a paper discharging table. A light source 2 and a first mirror 3 for illuminating a document placed on the document table 1 while scanning the document are integrally fixed to a first mirror table 4. Similarly, the second mirror 5 and the third mirror 6 are integrally fixed to the second mirror base 7. The first mirror base 4 and the second mirror base 7 are moved from the positions X2a and X3a to X2b and X3b by a driving unit (not shown) during scanning.
Are driven in synchronization with each other. An image forming lens 8 is provided at a position where the light beam from the third mirror 6 is received, and a light beam from the image forming lens 8 is reflected by a fourth mirror 9 so that an image of a document is formed on a photosensitive drum 10 as an image carrier. Make them image. The first mirror base 4 and the second mirror base 7 are driven so as to maintain an optical conjugate relationship between the document surface and the light receiving surface on the photosensitive drum 10, and scan and expose the image on the document surface. The photosensitive drum 10 is provided with a series of units for forming a toner image on a transfer material. The photosensitive drum 10 is the first mirror base 4,
A primary charger 11 is provided which rotates in the direction of the arrow in the figure in synchronization with the scanning operation of the second mirror base 7 and uniformly increases the surface potential of the photosensitive drum 10, and then the light flux from the document surface is changed to the fourth direction. An electrostatic latent image is formed on the receiving photosensitive drum 10 from the mirror 9. This electrostatic latent image is developed by the developing device 12 and becomes a toner image. The toner images are fed one by one from the paper feeding unit 13 and a pair of registration rollers 14 as a conveying unit.
The image is transferred by the transfer charging device 15 onto the transfer material that is conveyed to the photosensitive drum 10 via the separation charging device 16 that separates the transfer material from the photosensitive drum 10, and then is transferred to the fixing device 18 by the transfer table 17. The fixing device 18 is composed of rollers 18a and 18b that are kept at a high temperature by a heater (not shown), and fixes the toner image on the transfer material by heating and pressing. After that, the transfer material on which the image is formed is discharged to the paper discharge table 19. When the toner image is transferred from the photosensitive drum 10 to the transfer material by the transfer charger 15, the residual toner remaining on the photosensitive drum 10 without being completely transferred follows the rotation of the photosensitive drum 10 and is a cleaner unit 2 as a collecting means.
It is scraped off from the surface of the photosensitive drum 10 by the cleaning blade 21 provided at 0 and collected in the cleaner unit 20. The collected residual toner is discharged from the cleaner section 20 by a conveying screw 24 that discharges the residual toner to the outside, and is conveyed by the residual toner conveying path 22 to a replenishing container 23 that replenishes the developing device 12 with toner. The residual toner conveyed to the replenishment container 23 from the conveyance path 22 is mixed with new toner directly replenished to the replenishment container 23 and used again for development.

(First Embodiment) Next, the foreign matter collecting portion of the image forming apparatus according to the first embodiment will be described with reference to FIG.
The registration roller pair 14 is composed of two different registration rollers 14a and a lower registration roller 14b, and has a driving unit (not shown) that is in contact with each other and is rotated at the same peripheral speed in the arrow direction shown in FIG. In the present embodiment, of the registration roller pair 14, the registration roller 14 that contacts the transfer surface side of the transfer material 25 onto which the toner image is transferred.
A conductive layer is provided on a. The registration roller 14a is formed by fixing a roller cylinder made of non-conductive resin to a roller shaft made of metal such as iron, and further forming a conductive layer of metal or the like on the surface of the roller cylinder by plating or the like.
The lower resist roller 14b forms a roller surface by fixing a non-conductive rubber to a roller shaft made of metal such as iron. Registration roller 14a and registration lower roller 14
b is provided longer than the length of the transfer material 25 conveyed between the two in the roller longitudinal direction. In the vicinity of the registration roller 14a, there is provided a foreign matter collecting container 26 as a foreign matter removing means which is fixed to the image forming apparatus main body within a range substantially parallel to the length of the transfer material 25 in the roller longitudinal direction. A scraper 27 made of an elastic resin material is fixed to the foreign matter collection container 26 within a range longer than the length of the transfer material 25 in the roller longitudinal direction, and the tip end thereof is in contact with the registration roller 14a. Before and after the registration roller pair 14, guide plates 28, 29, 30, as guide means made of a conductive material for guiding the transfer material,
31 is provided. Guide plates 28, 29, 30, 3
1 is longer than the length of the transfer material 25 in the roller longitudinal direction. The conductive layer on the surface of the resist roller 14a is electrically connected to the voltage applying section A.
The second voltage applying section B is electrically connected to the conductive guide plate 31 and operates as a charging unit. The guide plate 31 and the guide plate 30 are electrically insulated.

Next, the operation of the foreign matter collecting section of the image forming apparatus according to this embodiment will be described. The transfer material 25 conveyed one by one from the paper feeding unit 13 is conveyed between the guide plates 30 and 31 and passes between the guide plates 30 and 31. In this embodiment, the guide plate 31 causes the transfer material 25 to move by the second voltage applying section B.
Applies a voltage of +2 KV when passing between the guide plates 30 and 31. Therefore, the transfer material 25 is charged and charged when passing through the position facing the guide plate 31 on which the voltage applying unit is installed. Similarly, the foreign matter on the transfer material 25 is also charged. As a result, the transfer surface of the transfer material 25 and the foreign matter on the transfer surface side are charged with a negative polarity. After that, the transfer material 25 reaches between the registration roller pair 14 and is driven by the driving means (not shown).
Rush to 4. A voltage of + 400V is applied to the conductive layer on the surface of the resist roller 14a by the voltage applying section A. Therefore, the foreign matter such as negatively charged paper powder attached on the transfer material 25 is attracted to the resist roller 14a by the electrostatic force acting between the transfer roller 25 and the resist roller 14a.
The adsorbed foreign matter is conveyed to the position of the scraper 27 as the resist roller 14a rotates, and scraped off from the resist roller 14a by the scraper 27,
It is recovered on the recovery container 26. After the foreign matter on the transfer material 25 is charged by the guide plate 31 in which the voltage applying section B is installed, the voltage applying section A keeps the surface of the resist roller 14a at a constant voltage in a stable manner to keep the surface of the resist roller 14a constant. Since the foreign matter can be reliably electrostatically attracted, the foreign matter is hardly present on the transfer material 25 after passing through the registration roller pair 14. Therefore, since the foreign matter that is adsorbed to the photosensitive drum 10 and scraped off by the cleaning blade 21 and collected in the cleaner unit 20 is almost eliminated, only the residual toner having a very small amount of foreign matter is collected in the cleaner unit 20. This residual toner is discharged from the cleaner unit 20 by a discharge screw 24 that discharges the residual toner to the outside.
The residual toner conveying path 22 conveys the toner to the replenishing container 23 for replenishing the developing device 12 with toner. The residual toner conveyed to the replenishment container 23 from the residual toner conveyance path 22 is mixed with new toner which is replenished directly to the replenishment container 23 and is used again for development. Since foreign matter is very little mixed in the residual toner to be reused, image deterioration such as fogging does not occur in the formed image, and a high quality image similar to that when using new toner is obtained. Can be guaranteed. Further, since a conductive guide plate for guiding the transfer material is used to charge the transfer material, a new member for constituting the charging means is unnecessary.

(Second Embodiment) FIG. 3 shows a schematic diagram of a second embodiment of the present invention.

In FIG. 3, the guide plate 31 has an opening 31.
A corona charger 32 is provided in the opening 31a as a charging unit that faces the transfer material 25 and has a length about the width of the transfer material 25. The second voltage applying section B is electrically connected to the corona charger 32.

Next, the operation of the foreign matter collecting section of the image forming apparatus according to this embodiment will be described. The transfer material 25 conveyed one by one from the paper supply unit 13 is conveyed between the guide plates 30 and 31 and passes through a position facing the corona charger 32. In the present embodiment, the corona charger 32 is applied with a voltage of +2 KV by the second voltage applying section B. Therefore, the transfer material 25 is charged and charged when passing through the position facing the corona charger 32. Similarly, the foreign matter on the transfer material 25 is also charged. As a result, the transfer surface of the transfer material 25 and the foreign matter on the transfer surface side are charged to the negative pole. After that, transfer material 2
5 reaches between the registration roller pair 14 and rushes into the registration roller pair 14 driven by a driving means (not shown). A voltage of + 400V is applied to the conductive layer on the surface of the resist roller 14a by the voltage applying section A. Therefore, the foreign matter such as negatively charged paper powder attached on the transfer material 25 is attracted to the resist roller 14a by the electrostatic force acting between the transfer roller 25 and the resist roller 14a. The adsorbed foreign matter is conveyed to the position of the scraper 27 according to the rotation of the resist roller 14a, scraped off from the resist roller 14a by the scraper 27, and collected in the foreign matter collection container 26. After the foreign substances on the transfer material 25 are charged by the corona charger 32, the voltage applying unit A stably holds the conductive layer on the surface of the resist roller 14a at a constant voltage to securely electrostatically attract these foreign substances. Therefore, there is almost no foreign matter on the transfer material 25 after passing through the registration roller pair 14. Therefore,
Since the foreign matter that is adsorbed by the photosensitive drum 10 and scraped off by the cleaning blade 21 and collected in the cleaner unit 20 is almost eliminated, only the residual toner having a very small amount of foreign matter is collected in the cleaner unit 20. The residual toner is discharged from the cleaner unit 20 by a discharge screw 24 that discharges the residual toner to the outside, and the residual toner conveying path 2
2, the replenishing container 23 that replenishes the developing device 12 with toner.
Be transported to. The residual toner conveyed to the replenishment container 23 from the conveyance path 22 is mixed with new toner directly replenished to the replenishment container 23 and used again for development. Since foreign matter is very little mixed in the residual toner to be reused, image deterioration such as fogging does not occur in the formed image, and a high quality image similar to that when using new toner is obtained. Can be guaranteed.

(Third Embodiment) A third embodiment of the image forming apparatus according to the present invention will be described with reference to the drawings. In this embodiment, the present invention is applied to a copying machine, and the overall configuration and operation of the image forming apparatus are the same as those of the embodiment shown in FIG.

The foreign matter collecting portion of the image forming apparatus according to this embodiment will be described with reference to FIG. In the third embodiment, the charging means by the corona charger 32 in the foreign matter collecting section in the second embodiment is replaced by the charging means by the charging roller 44a. 1 to 3 of the constituent members of FIG.
Since the components having the same numbers as those of the above-mentioned components have the same configuration and operation, the description thereof will be omitted. Registration roller pair 14
Guide plate 4 for guiding the upstream transfer material in the transfer material transport direction
The guide plate 40, which is composed of four parts 0, 41, 42, 43,
A roller pair 44 including a charging roller 44a and an auxiliary roller 44b is arranged between 41 and 42, 43. The charging roller 44a is a roller made of conductive rubber and is electrically connected to the second voltage applying section B.
The auxiliary roller 44b is a roller made of insulating rubber or the like and is electrically insulated from the charging roller 44a.

Next, the operation of the foreign matter collecting section of the image forming apparatus according to the third embodiment will be described. The transfer material 25 conveyed one by one from the paper feeding unit 13 is conveyed between the guide plates 40 and 41 and reaches the charging roller 44a and the auxiliary roller 44b. The charging roller 44a and the auxiliary roller 44b have a driving unit (not shown) and sandwich the transfer material 25 to convey it. In this embodiment, the charging roller 44a is applied with a voltage of +2 KV by the second voltage applying section B. Therefore, the transfer material 25 is charged by being charged when passing through the position facing the charging roller 44a. Similarly, the foreign matter on the transfer material 25 is also charged. After that, the transfer material 25 reaches between the registration roller pair 14 and rushes into the registration roller pair 14 driven by a driving unit (not shown). A voltage of + 400V is applied to the conductive layer on the surface of the resist roller 14a by the voltage applying section A. Therefore, the foreign matter such as the charged paper powder attached on the transfer material 25 is attracted to the resist roller 14a by the electrostatic force acting between the transfer material 25 and the resist roller 14a. The adsorbed foreign matter is conveyed to the position of the scraper 27 according to the rotation of the resist roller 14a, scraped off from the resist roller 14a by the scraper 27, and collected in the foreign matter collection container 26. After the foreign matter on the transfer material 25 is charged by the charging roller 44a, the conductive layer on the surface of the resist roller 14a is stably maintained at a constant voltage by the voltage application unit A, so that the foreign matter is reliably electrostatically adsorbed. Therefore, there is almost no foreign matter on the transfer material 25 after passing through the registration roller pair 14. Therefore, since the foreign matter that is adsorbed to the photosensitive drum 10 and scraped off by the cleaning blade 21 and collected in the cleaner unit 20 is almost eliminated, only the residual toner having a very small amount of foreign matter is collected in the cleaner unit 20. The residual toner is discharged from the cleaner unit 20 by a discharge screw 24 that discharges the residual toner to the outside, and is conveyed by a residual toner conveying path 22 to a replenishing container 23 that replenishes the developing device 12 with toner. The residual toner conveyed to the replenishment container 23 from the conveyance path 22 is mixed with new toner directly replenished to the replenishment container 23 and used again for development. Since foreign matter is very little mixed in the residual toner to be reused, image deterioration such as fogging does not occur in the formed image, and a high quality image similar to that when using a new toner is obtained. Can be guaranteed.

(Fourth Embodiment) The fourth embodiment of the image forming apparatus according to the present invention will be described with reference to FIG. In this embodiment, the present invention is applied to a copying machine, and the overall configuration and operation of the image forming apparatus are the same as those of the embodiment shown in FIG.

The foreign matter collecting section of the image forming apparatus according to this embodiment will be described with reference to FIG. In the fourth embodiment, the charging means by the corona charger 32 of the foreign matter collecting section in the second embodiment is replaced by the charging means by the brush charger 50a. Of the constituent members in FIG. 5, those having the same reference numerals as those in the constituent members in FIGS. 1 to 4 are members having the same configuration and operation and will not be described. The guide plate that guides the transfer material upstream of the registration roller pair 14 in the transfer material conveyance direction is 4
The guide plate 40, which is composed of four parts 0, 41, 42, 43,
A brush charger 50a and an auxiliary roller 50b are arranged between 41, 42 and 43. Brush charger 50a
Is a fibrous conductive brush and is electrically connected to the second voltage applying section B. The auxiliary roller 50b is a roller made of insulating rubber or the like and is electrically insulated from the brush charger 50a.

Next, the operation of the foreign matter collecting portion of the image forming apparatus according to the fourth embodiment will be described. The transfer material 25 conveyed one by one from the paper supply unit 13 is conveyed between the guide plates 40 and 41 and reaches the brush charger 50a and the auxiliary roller 50b. The brush charger 50a and the auxiliary roller 50b have a driving unit (not shown) and sandwich the transfer material 25 to convey it. In this embodiment, the brush charger 50a is applied with a voltage of +2 KV by the second voltage applying section B. Therefore, the transfer material 25 is charged and charged when passing through the position facing the brush charger 50a. Similarly, the foreign matter on the transfer material 25 is also charged. After that, the transfer material 25 reaches between the registration roller pair 14 and rushes into the registration roller pair 14 driven by a driving unit (not shown). A voltage of + 400V is applied to the conductive layer on the surface of the resist roller 14a by the voltage applying section A. Therefore, the foreign matter such as the charged paper powder attached on the transfer material 25 is attracted to the resist roller 14a by the electrostatic force acting between the transfer material 25 and the resist roller 14a. The adsorbed foreign matter is conveyed to the position of the scraper 27 according to the rotation of the resist roller 14a, scraped off from the resist roller 14a by the scraper 27, and collected in the foreign matter collection container 26. After the foreign matter on the transfer material 25 is charged by the brush charger 50a, the conductive layer on the surface of the resist roller 14a is stably maintained at a constant voltage by the voltage application unit A, so that the foreign matter is securely electrostatically attracted. Therefore, there is almost no foreign matter on the transfer material 25 after passing through the registration roller pair 14. Therefore, since the foreign matter that is adsorbed by the photosensitive drum 10 and scraped off by the cleaning blade 21 and collected in the cleaner section 20 is almost eliminated, only the residual toner having a very small amount of foreign matter is collected in the cleaner section 20. The residual toner is discharged from the cleaner unit 20 by a discharge screw 24 that discharges the residual toner to the outside, and is conveyed by a residual toner conveying path 22 to a replenishing container 23 that replenishes the developing device 12 with toner. The residual toner conveyed to the replenishment container 23 from the conveyance path 22 is mixed with new toner directly replenished to the replenishment container 23 and used again for development. Since foreign matter is very little mixed in the residual toner to be reused, image deterioration such as fogging does not occur in the formed image, and a high quality image similar to that when using new toner is obtained. Can be guaranteed.

[0032]

According to the present invention having the above-mentioned structure and operation, the charging means for charging the transfer material is provided on the upstream side of the carrying means in the carrying direction, so that when the transfer material passes the position facing the charging means. The transfer material and the foreign material on the transfer material are charged and charged, and the foreign material on the transfer material can be reliably removed by applying the electric charge so that the foreign material adheres to the conveying means.

Further, a member in which foreign matter is arranged around the image carrier (eg, an electrode of a charger, a light emitting / receiving portion of an optical sensor, etc.).
It does not adhere to the surface and the performance does not deteriorate.

As a result, it is possible to prevent foreign matter from being mixed into the toner remaining on the image carrier and collected, and to provide an image forming apparatus capable of obtaining a high-quality image without fogging.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an image forming apparatus that is an embodiment of the present invention.

FIG. 2 is a schematic view of a main part of the image forming apparatus according to the first embodiment of the present invention.

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

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

FIG. 5 is a schematic view of a main part of an image forming apparatus according to a fourth embodiment of the present invention.

FIG. 6 is a schematic view of a main part of a conventional image forming apparatus.

[Explanation of symbols]

 A, A'voltage applying section B second voltage applying section 10, 11 photosensitive drum (image carrier) 14 registration roller pair (conveying means) 20,113 cleaner section (collecting means) 25,105 transfer material 26,110 foreign matter collecting Container (foreign matter removing means) 27,109 Scraper (foreign matter removing means) 31 Guide plate (guide means / charging means) 32 Corona charger (charging means) 44a Charging roller (charging means) 50a Brush charger (charging means)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G03G 15/045

Claims (7)

[Claims] 1. A conveying means for conveying a transfer material, a foreign matter removing means attached to the conveying means, a voltage applying means for applying a voltage to the conveying means, an image carrier, and the image carrier. An image forming apparatus comprising: a collecting unit that collects toner remaining on the upper surface of the image forming apparatus; and a charging unit that charges a transfer material on the upstream side of the conveying unit in the conveying direction. 2. The image forming apparatus according to claim 1, wherein the charging unit is a guiding unit that guides the transfer material, and is connected to a second voltage applying unit that applies a voltage. 3. The image forming apparatus according to claim 1, wherein the charging unit is a corona charger. 4. The image forming apparatus according to claim 1, wherein the charging unit is a charging roller. 5. The image forming apparatus, wherein the charging unit is a brush charger including a conductive brush. 6. The image forming apparatus according to claim 1, wherein the conveying unit is a roller, and a scraper is brought into contact with the roller substantially in parallel with the roller. . 7. The image forming apparatus according to claim 6, wherein a container is provided at an end of the scraper that is not in contact with the roller, substantially parallel to the scraper.