JPH11149206A - Image recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the adhesion of toner to the brush charger by arranging a scraper on a brush charger for charging a photosensitive drum in a photosensitive unit constituting a process device by combining with a developing device unit. SOLUTION: In a photosensitive unit 60 arranged on a process device, a scraper 67 is arranged against a brush charge 65 charging a photoreceptor drum 62 to eliminate the adhesion of toner in-between bristles of the brush. Thereby, the occurrence of the dirt of the brush charger 65 is prevented so that charging action against the photosensitive drum 62 can be excellently conducted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charger which is preferably disposed in a cleaner-less type image forming apparatus, and more particularly to an image recording apparatus which can easily remove stains such as toner adhering to a roll-shaped brush charger. Related to the device.

[0002]

2. Description of the Related Art In an electrophotographic image recording apparatus, a charging corotron which performs corotron discharge is generally used as a charging means for a photosensitive drum. Then, after setting the surface potential of the photosensitive drum to a constant value by discharging the charging corotron, an image is irradiated to form an electrostatic latent image, and toner is supplied to the electrostatic latent image. By doing so, a visible image as a toner image is created. The toner image is transferred to a sheet at an image transfer position using a transfer corotron or the like, and the sheet carrying the toner image is fixed through a fixing device and discharged as a recording sheet. However, in the image recording apparatus using the corotron, there is a problem that ozone is generated by high-pressure discharge from the corotron.

[0003] For a small-sized image recording apparatus, a charging device for charging a photosensitive drum and a transfer member for transferring a toner image to paper are formed by brushes (brush charging device). Alternatively, a roll-shaped member made of a sponge is used. For example, by using a brush charger, the configuration of the image forming apparatus can be simplified, the discharge voltage is set to a relatively low voltage, and the generation of ozone is eliminated. It is possible to exhibit the feature that the configuration can be simplified.

[0004]

However, when the above-mentioned brush charger is used, toner may enter between the bristles of the brush and adhere thereto, or paper dust or the like separated from the paper may adhere to cause contamination. There is. When the brush becomes dirty, the charging performance may be deteriorated. In addition, when the brush is soiled, the surface of the photosensitive drum cannot be uniformly charged when affected by environmental conditions (change in humidity). The problem occurs. In particular, in an image forming apparatus of a system (cleanerless system) in which a toner image is transferred from a photosensitive drum onto a sheet, and the remaining toner is returned to a developing device without being collected by a cleaning device and is reused. Since the toner and the like remaining on the body drum are not removed before charging, the brush charger is easily stained compared to a system using a cleaning device, and the stain on the brush charger greatly affects the charging performance of the photosensitive drum. Things.

The present invention solves the above-described problem of the brush charger being stained, and provides means for contacting a plate-shaped member with the brush charger to easily remove the brush stain. It is an object to provide an image recording device that enables it.

[0006]

SUMMARY OF THE INVENTION According to the present invention, there is provided a system in which a brush charger which is slid and rotated on a photosensitive drum is arranged to uniformly charge the photosensitive drum before irradiating the photosensitive drum with light of an image. Related to an image forming apparatus. The invention according to claim 1 of the present invention is characterized in that a plate-shaped contact member is arranged with respect to the brush charger and is brought into contact with the surface of the brush charger. According to a second aspect of the present invention, the photosensitive drum of the image forming apparatus is configured as a unit including the photosensitive drum and a brush charger. It is characterized by contact. According to a third aspect of the present invention, in the structure in which a plate-shaped contact member is arranged with respect to the brush charger, a toner image formed on the photosensitive drum is transferred to a sheet, and then the toner remaining on the photosensitive drum is developed. It is characterized in that it is incorporated into an apparatus of the type that can be returned to a container and reused.

[0007] With the above-described structure, the plate-shaped contact member (hereinafter referred to as a scraper) slides on the rotating brush charger to constantly scrape off the toner and paper powder accumulated on the brush, thereby making it possible to brush the brush. Can be prevented from adhering to the surface. Further, by configuring the photosensitive drum, the brush charger, and the scraper as one unit, handling and maintenance of the unit can be easily performed. Further, by incorporating the unit of the present invention into a cleanerless type apparatus, the features of the image recording apparatus can be effectively utilized.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of an image recording apparatus according to the present invention will be described with reference to the illustrated example. The example shown in FIG. 1 shows a case in which a facsimile machine and a copying machine are configured as a combined device.
Two paper cassettes 3 and 3a are arranged at the lower part, and can be swung via a main frame 2 provided with an electrophotographic recording unit at the upper part thereof and a fulcrum 21 provided at one side of the main frame 2 And the scanning unit frame 20 provided in the first embodiment. A scanning device as an FBS for arranging a platen on the upper surface of the scanning unit frame 20 and scanning an original of a book set on the platen;
The upper surface of the platen cover is used as a document discharge tray 28, and a document to be inserted from the document tray 27 is scanned while being moved in a document feeder 40 as an automatic document feeder, and an operation as an automatic document feeder (ADF) is performed. And a moving document scanning unit for performing the scanning. In the image recording apparatus 1, as shown by a virtual line in FIG. 1, the scanning unit frame 20 is configured to be openable and closable with respect to the main body frame. In the open state, the upper surface of the main body frame 2 is open.

By arranging the components and the frame opening / closing mechanism, in the image recording apparatus of the present invention, the operation of replenishing the paper into the paper feed cassette and controlling the apparatus can be performed from the front side. The operations of feeding the paper using the tray and taking out the copy can be performed from both sides. Further, by opening and closing the scanning unit frame 20, the upper part of the main body frame is opened so that the maintenance of the process unit of the image recording unit can be performed. Further, the operation of setting the original of the book on the platen can be performed by opening and closing the upper opening / closing frame 25 on the scanning unit frame 20, and transmitting the image information while scanning the original set on the platen. Can be easily performed.

The paper feed cassettes 3 and 3a accommodated in the lower portion of the main body frame 2 are capable of accommodating sheets of an arbitrary size and are provided so as to be drawn out to the front side of the apparatus. As shown in FIG. 3, a manual insertion slot 5 is disposed on the other side of the main body frame so that a manual tray 6 can be mounted thereon. A copy can be made using a small number of sheets that cannot be accommodated in the main body frame. When the manual feed tray is not mounted, there is no protrusion on the side surface of the main body frame. Further, as shown in FIGS. 1 and 3, a discharge tray 7 for storing a copy is disposed on one side of the main body frame 2, and an auxiliary tray 8 is provided corresponding to a large-sized sheet.
Is provided so that it can be pulled out. When the auxiliary tray is not pulled out, the discharge tray 7 is moved to the scanning unit frame 20.
Since the paper does not protrude to the side than the end of the paper, the paper is stored in a state of protruding slightly from the tray.

In the image recording apparatus 1, the scanning unit frame 20 arranged above the main frame 2 is provided with a scanning device 30 configured as shown in FIG. The scanning device 30 includes a full-rate carriage 31 provided with a lamp 32 and one mirror m1, and two opposed mirrors m2 and m3, similar to those used in a reading device of a general copying machine or image recording device. Is provided in combination with a half-rate carriage 33 for disposing the document, scanning information of the document is transmitted to the CCD 38 via the lens device 37, an optical signal is converted into an electric signal, and transmitted to an image information processing section disposed on the main body frame. . In order to drive the full rate carriage 31 and the half rate carriage 33, in the present embodiment, a driving pulley 35 having a diameter set to 2: 1 is used.
A mechanism is provided in which the two carriages are moved cooperatively via belts 36 and 36a which are arranged coaxially with the respective drive pulleys.

On the upper part of the scanning unit frame 20, a book original is placed, and a platen 23 corresponding to an operation as an FBS and a platen 23 corresponding to an operation as an ADF are provided.
A platen 24 is provided below the document feeder 40. With respect to the platen 23, the document is set by opening the upper opening / closing frame 25, and by closing the upper opening / closing frame, the platen cover 26 presses the image surface of the document against the upper surface of the platen, and is set at the fixed position. Scan the original. For the original set on the platen 23, the full-rate carriage 31 of the scanning device 30 reciprocates by the length of the original in the scanning direction according to the detection information of a sensor (not shown). Reads image information while moving at half the speed of the full-rate carriage, and outputs image signals via the CCD. When scanning a document on a sheet using the document tray 27, the document is transported through a U-shaped transport path 44 provided in a document transport unit 40 as an ADF (automatic document transport device). The operation of reading an image is performed in a state where the scanning device is fixed.

U-shaped transport path 4 provided in document transport section 40
4, a pickup roller 42 of a document insertion section, a sheet separating device 43, and a transport roller device 45 for transporting the document inside the U-shaped transport path are provided. The transport roller device 45 includes a large-diameter drive roller 46 that forms a guide surface for an inner surface of a turn portion of a document, and two pinch rollers 4.
7 and 47a, and the platen 24 is positioned downstream of the pinch roller 47a. A discharge roller device 48 is disposed at the end of the U-shaped conveyance path 44, and discharges the scanned document toward the discharge tray 28.

The original transport section 40 has a U-shaped transport path 44
An open / close frame 41 integrally provided with a paper guide on the outside thereof is provided so as to be openable and closable via a support shaft 40a. The open / close frame 41 includes a pickup roller 42, a roller of a paper separating device 43, and pinch rollers 47, 47a. Has been arranged. Then, by opening the opening / closing frame 41, the U-shaped conveyance path 44 is opened so that the jammed paper can be processed. Although not shown, a frame including the guide plate and the driving roller 46 inside the U-shaped conveyance path 44 and one roller of the discharge roller device 48 is used.
When the platen 24 is provided so as to be openable and closable with respect to the lower frame of the document transport unit, maintenance such as cleaning of the platen 24 can be easily performed.

When scanning the original set on the original tray 27 by using the original transport unit 40, the control unit detects that the original has been set on the original tray by a detection signal of a detection unit (not shown). The operation is performed by inputting a command for reading an image using the document conveying unit on the control panel. And according to the signal,
The full rate carriage 31 of the scanning device 30 is moved to the platen 2
4, the half-rate carriage 33 is moved to the left end of the scanning unit frame 30, and the U-shaped conveyance path 44 is used to transfer the documents one by one from the document tray 27.
And read the image of the original at the platen 24. Therefore, in the scanning device arranged on the scanning unit frame 20, the scanning device can be set in correspondence with the two platens 23 and 24, and an operation of reading an arbitrary document can be performed. , Image information can be transmitted.

A main body frame 2 disposed below the original conveying section 40 has a process device 50 using an electrophotographic system as shown in FIG. 3 and a paper conveying mechanism from a paper feed cassette to a discharge tray. Are provided. The process device 50 includes a developing unit 51 and a photosensitive unit 60.
The developing roller of the developing unit 50 is disposed with respect to the photosensitive drum 62 provided in the photosensitive unit 60, and a transfer roller is provided below the photosensitive drum 62 so as to sandwich a paper passage. 17 are provided.
Two units 51 constituting the process device 50,
As will be described later, 60 is provided detachably from the upper part of the main body frame while being integrally assembled.
Is closed and held in the operating position.

In the paper feed cassette 3 disposed below the process device of the main body frame, the paper is fed one by one by a paper feed roller 13 disposed on the paper feed side, and the paper is conveyed in a paper conveyance path 14 so that an image is formed. Through the transfer unit,
The sheet is sent to the fixing device 18 and discharged toward a discharge tray via a discharge roller device 19. The paper transport path 14 is provided with a transport roller device 15 and a registration roller device 16. When the leading end of the paper is nipped by the transport roller device 15, the feeding action by the paper feed roller 13 is interrupted,
The sheet is fed by the transport roller device 15, and the leading end of the sheet is stopped by the registration roller device. Then, according to the timing of the toner image formed on the photosensitive drum 62, the transport roller device 16 is driven to send out the sheet, and the toner image is transferred to the sheet by applying a voltage from the transfer roller 17. Then, the sheet on which the toner image has been transferred is guided to the fixing device 18 by the sheet feeding action of the photosensitive drum, and is fixed between the heat roller and the pressure roller of the fixing device 18, and the copy is discharged. The sheet is discharged to a discharge tray by the device 19.

In the apparatus shown in FIG. 1, two paper cassettes are arranged in the paper supply section, but the paper cassettes below the paper cassette 3 are transported through the paper transport path 14a through the paper transport path 14a. Sent to Further, the paper supplied through a manual tray provided in the manual insertion slot 5 is sent to a registration roller 16 via a manual roller device 5a, and the image is transferred. In the vertical paper transport path of the main body frame, means for opening the paper transport path with the side plate 4 opened is provided, and by opening the paper transport path further larger than the state shown by the imaginary line in the figure, the vertical Processing of paper in the paper transport path can be performed. For the side plate 4, a lock mechanism and a detecting means are provided on the main body frame so that the sheet can be conveyed only in a state where the side plate is closed.

In the process device 50 disposed above the horizontal portion of the paper transport path 14, a writing device 70 is disposed above the photosensitive drum 62 of the photosensitive unit 60, and the writing device 70 is provided with an intermediate cover. It is provided so as to be positioned with respect to the photosensitive drum in a state where 10 is closed. The process device 50 is configured as a cleaner-less type device. A conventional cleaning device is disposed on the photosensitive drum, and after the toner image is transferred to the paper, the toner image adheres to the photosensitive drum and remains. It has a configuration different from that for recovering toner to be used. The two units of the developing device unit 51 and the photoreceptor unit 60 constituting the process device are detachably mounted on the holding unit of the main body frame while the two units are combined.

A stirrer 53 for supplying the toner to the supply roller 54 while stirring the toner is disposed in the container portion 52 of the developing unit 51 for storing the non-magnetic one-component toner. A supply roller 54 and a developing roller 5 in contact with the photosensitive drum 62 are provided at a toner discharge portion from the container portion 52.
5 and a layer thickness regulating member 5 in contact with the developing roller 55
6 is provided. The agitating member 53 supplies the toner to the supply roller 54 while agitating the toner, and can be configured as a member provided with an arbitrary blade member or a rod-shaped member. Further, the supply roller 54 can be configured as an elastic roller provided with a predetermined thickness of a spongy conductive elastic body or a flocking body having conductive fibers on the shaft. A bias voltage having a value of -500 to -700 V, preferably about -600 V is applied to the shaft of the supply roller 54 from a power supply member (not shown).

The developing roller 55 is made of a metal roller shaft made of stainless steel or the like and covered with a conductive rubber (silicon rubber, urethane rubber, NBR) with a predetermined thickness. The surface is configured to be smooth. For the developing roller 55, -200 to-
A bias voltage having a value of about 400 V, preferably about -300 V is applied. The layer thickness regulating member 56 disposed with respect to the developing roller 55 is for uniformly forming a thin layer of toner on the surface of the developing roller 55, and is formed of a urethane resin sheet or a stainless steel plate member. It is configured as having spring properties. For the layer thickness regulating member 56, a range of -300V to -500V,
Preferably, a bias voltage having a value of about -400 V is applied.

The center distance between the supply roller 54 and the developing roller 55 is set to be slightly smaller than the sum of the radii of the two rollers, and by rotating both rollers in the same direction (the direction of arrow X). At the contact portion between the two rollers, the roller is slid in the opposite direction while being pressed. Then, the toner is charged between the two rollers and the toner adheres to the surface of the developing roller 55 due to the friction between the two rollers and the difference between the voltages applied to the respective rollers.
Further, the toner adhered to the surface of the developing roller 55 is formed to a uniform thickness by the layer thickness regulating member 56, exposed to the photosensitive drum, and transferred to the latent image formed on the photosensitive drum. Thus, a toner image is formed.

As shown in FIGS. 5 and 6, the photosensitive unit 60 arranged in combination with the developing unit 51 has a photosensitive drum 62 supported by a unit frame 61, and a surface formed of a flocked member or the like. And a brush charger 65 such as a brush roller. And
A writing unit 70 is arranged on the photosensitive drum 62 to write an image, and the toner image formed on the photosensitive drum is transferred to a sheet by discharging the transfer roller 17. The writing unit 70 includes an LED head array, and emits light to irradiate the photosensitive drum with light based on information from an image information output device. The surface of the photosensitive drum 62 is made of a grounded photoconductor, and a brush charger 65 is provided.
To −780 V, and the writing unit 7
From 0, the potential of the portion irradiated with light, that is, the potential of the portion of the image information with respect to black becomes about -80 V, and a potential difference occurs between the portion irradiated with light and the non-irradiated portion (the portion corresponding to the white of the image information). Is formed.

With respect to the electrostatic latent image formed on the photosensitive drum, approximately -68 attached to the surface of the developing roller 55
When the toner charged to 0 V comes into contact with the toner, the toner is attracted to the light irradiation site on the surface of the photosensitive drum 62, and a toner image is formed on the surface of the photosensitive drum (reversal development). At the transfer position of the toner image, the transfer roller 17 applies a bias voltage of 800 to 2 kV from the back surface of the sheet, so that the toner image is transferred to the sheet. The sheet on which the toner image has been transferred is sent to the fixing device 18 by the rotation of the photosensitive drum.

After the toner image is transferred onto the paper, the toner remaining on the surface of the photosensitive drum is disturbed by a memory removing brush 66 disposed downstream of the transfer roller 17 so as to be in contact with the drum surface. And is dispersed on the surface of the photosensitive drum, and the subsequent brush charger 6
5 is charged to the same potential as the surface of the photosensitive drum. A predetermined voltage (preferably 300 V) is applied to the memory removal brush 66 in order to effectively disturb the toner on the drum surface. Then, at a position where the photosensitive drum is in contact with the developing roller 55, the cleaner is transferred to the developing roller 55 side by a potential difference between the two, mixed with toner newly supplied from the container portion, and reused. It is configured as a device of the less system.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A photoreceptor unit 60 provided in the process unit 50 is constructed as shown in FIG.
Before an image is written by the writing device, a brush charger 65 is arranged to uniformly charge the surface of the photosensitive drum 62. The brush charger 65 is configured as a brush roller provided with a conductive flocking member with respect to a metal shaft. After the toner image is transferred to paper, the surface of the photosensitive drum is newly charged. Perform the action. Further, a memory removing brush 66 is disposed upstream of the brush charger 65. After the toner image is transferred onto the paper, the toner remaining on the surface of the photosensitive drum is scraped by the memory removing brush 66. The toner is disturbed and dispersed on the surface of the photosensitive drum, and is charged to the same potential as the surface of the photosensitive drum by the operation of the brush charger 65 thereafter. Then, at a position where the photosensitive drum is in contact with the developing roller 55, the cleaner is transferred to the developing roller 55 side by a potential difference between the two, mixed with toner newly supplied from the container portion, and reused. It is configured as a device of the less system. However, the brush charger 6
During the flocking of No. 5, toner and paper dust released from the photoreceptor drum enter and cause problems such as deterioration of charging performance.

Therefore, a scraper 67 is provided for the brush charger 65 in order to prevent the toner from adhering to the brush charger 65 and thereby impairing the charging performance. The scraper 67 is made of sheet metal, and its base is attached to the unit frame 61 of the photoreceptor unit 60, and the tip of the scraper is arranged so as to bite into the brush of the brush charger 65 by several mm. The sliding of the surface of 65 causes the toner or paper powder or the like that has entered during the flocking to be wiped off. In this embodiment, the brush charger 6
In a stage before the brush member 66 is disposed upstream of the photosensitive drum 5 to charge the photosensitive drum, the toner adhering to the photosensitive drum is disturbed and dispersed.
, So that a charging action can be imparted.

The scraper 67 disposed with respect to the brush charger 65 can be disposed by projecting a simple single plate-like member into the unit frame 61.
By sliding the scraper 67 against the surface of the rotating brush charger 65, the scraper 67 has an action of sweeping off toner or the like that tends to stay between the brushes of the brush charger 65,
The removed toner and the like accumulate at the bottom of the unit. The amount of toner and the like that accumulates at the bottom is very small in practice, does not overflow from the unit until the life of the photosensitive unit, and is discarded when the unit is replaced.

FIG. 6 shows an example in which the scraper 68 disposed with respect to the brush charger 65 is made of a resin material. The scraper 68 is made of the same material as that of the unit frame. It can be formed integrally with the frame. If the scraper 68 cannot be integrally formed with the unit frame, a unit made of an arbitrary resin material is attached to the unit frame by means of adhesion or the like, and is fixed to the brush charger 65 at a predetermined depth. It can be arranged so as to bite. And, the scraper 68
In the above, the portion in contact with the brush charger is plate-shaped, but an arbitrary hole or the like is formed in the base portion, and while the brushed toner and the like float inside the space of the unit frame, the photosensitive drum is To a structure that can be attached again and recovered.

As described above, the scraper is disposed with respect to the brush charger, and a mechanism for removing toner or the like that has entered during the implantation of the brush charger is used. It is provided integrally with the frame. Therefore, after the process device is incorporated into the device main body, it is not necessary to adjust conditions such as the depth at which the tip of the scraper bites into the brush charger. Further, since the material of the scraper can be made of any material in accordance with the material of the brush of the brush charger, the brush charger can be configured in accordance with conditions such as the number of copies that can be made in the unit. It is also possible to set the life of the scraper and the scraper. Further, in the embodiment of the present invention, the processing device is configured by combining the developing unit and the photoconductor unit, but an arbitrary mechanism can be used as a connecting means of the two units. It is also possible to attach and detach the two units to and from the main body frame in a state in which the two units are combined, or to configure each unit to be individually mountable on the main body frame.

[0031]

According to the apparatus of the present invention, since the plate-shaped scraper is slid on the rotating brush charger, the toner and paper powder accumulated on the brush are constantly scraped off because of the construction as described above. It is possible to prevent dirt from attaching to the brush. Further, by configuring the photosensitive drum, the brush charger, and the scraper as one unit, handling and maintenance of the unit can be easily performed. Further, by incorporating the unit of the present invention into a cleaner-less type apparatus, the characteristics of the image recording apparatus can be effectively utilized in combination with the developing unit.

[Brief description of the drawings]

FIG. 1 is an external view of an image recording apparatus according to the present invention.

FIG. 2 is an explanatory diagram illustrating a configuration of a scanning device used by being incorporated in the device of FIG. 1;

FIG. 3 is an explanatory view of an apparatus arranged on a main body frame of FIG. 1;

FIG. 4 is an explanatory diagram illustrating a configuration of the process device of FIG. 3;

FIG. 5 is an explanatory diagram illustrating a configuration of a photoconductor unit of the present invention.

FIG. 6 is an explanatory diagram of another embodiment of the photoconductor unit.

[Explanation of symbols]

1 image recording device, 2 body frame, 3
Paper feed cassette, 10 intermediate lid, 13 paper feed roller, 14 paper transport path, 15.16 transport roller device, 17 transfer roller, 18 fixing device, 19
Discharge roller device, 20 scanning unit frame, 23
・ 24 platen, 26 platen cover, 27
Document tray, 30 scanning device, 31 full rate carriage, 33 half rate carriage,
35 drive pulley, 37 lens, 38 C
CD, 40 original transport section, 44 U-shaped transport path,
45 transport roller device, 50 process device, 5
1 developing unit, 55 developing roller, 60
Photoconductor unit, 61 Unit frame, 65
Brush charger, 66 Brush member, 67, 68
Scraper, 70 writing device.

Claims (3)

[Claims] 1. An image forming apparatus of a system in which a brush charger which is rotated while being slid on a photosensitive drum is arranged to uniformly charge the photosensitive drum before irradiating image light to the photosensitive drum. An image recording apparatus, wherein a plate-shaped contact member is disposed with respect to a charger and is brought into contact with a surface of the brush charger. 2. The photosensitive drum of the image forming apparatus is configured as a unit including a photosensitive drum and a brush charger, and the unit is provided with a plate-shaped contact member.
2. The image recording apparatus according to claim 1, wherein the image recording apparatus is brought into contact with a brush charger. 3. A structure in which a plate-shaped contact member is arranged with respect to the brush charger, the toner remaining on the photosensitive drum is transferred to a developing device after a toner image formed on the photosensitive drum is transferred to paper. The image recording apparatus according to claim 1, wherein the image recording apparatus is incorporated in an apparatus of a type that is returned and reused.