JPH11149199A - Image recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable excellent electrifying action with a brush electrifier by eliminating the soiling and fur tilt of the brush electrifier provided with respect to a photoreceptor drum, in a photoreceptor unit which constitutes a process device in combination with a developing unit. SOLUTION: In the photoreceptor unit 60 arranged in the process device in this image recorder, the brush electrifier 65 for imparting electrifying action to the photoreceptor drum 62 is arranged to attain uniform electrification and a mechanism for driving the brush electrifier 65 to reversely rotate it after a copying operation is completed, for instance, is provided. Then, the brush electrifier 65 is rotated in a reverse rotational direction (X1), to correct the fur tilt of the brush of the electrifier 65 and the action of shaking toner, etc., can be taken.

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 recording apparatus, and more particularly, to a method for removing toner stains adhering to a roll-shaped brush charger and reducing brush hair fall. It relates to a device that can be easily corrected.

[0002]

2. Description of the Related Art In an electrophotographic image recording apparatus,
Generally, a charging corotron that performs corotron discharge is used as a charging unit for the photosensitive drum. And
After setting the surface potential of the photosensitive drum to a constant value by discharging the charging corotron, irradiating image light to form an electrostatic latent image, and supplying toner to the electrostatic latent image Thus, 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 onto paper are formed by brush-like rollers (brush charging). ) Or a roll-shaped member formed of sponge.
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. Can be simplified.

[0004]

However, when the above-mentioned brush charger is used, toner or paper dust may enter between the brush hairs and adhere to the brush, causing stains on the brush. When the brush is soiled, the charging performance for the photosensitive drum decreases, and when the brush is soiled, the surface of the photosensitive drum cannot be uniformly charged when affected by environmental conditions (changes in humidity). The problem occurs. Further, since the brush charger is rotated in the same direction while being constantly pressed against the photoconductor drum, the bristles of the brush slide on the surface of the photoconductor drum and are directed in the rotation direction of the photoconductor drum. The brush bristles fall down to one side due to the action of falling down strongly, and it is difficult to remove the toner that has entered between the brush bristles. 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.

SUMMARY OF THE INVENTION The present invention solves the problem of hair fall and dirt of a brush charger arranged on a photosensitive drum.
The brush charger alone or the photoreceptor drum and the brush charger are rotated in the opposite direction at a predetermined timing to correct the brush fall of the brush charger and remove the dirt from the brush charger. It is intended to provide.

[0006]

SUMMARY OF THE INVENTION The present invention relates to an image recording apparatus of the type in which a charging device is arranged on a photosensitive drum and uniform charging is performed before irradiating the photosensitive drum with image light. The invention according to claim 1 of the present invention is characterized in that the charging device is constituted by a brush charging device, and is pressed against the photosensitive drum to rotate in the same direction. It is characterized in that it is driven in a direction opposite to the rotation direction for a predetermined time. The invention according to claim 2 is characterized in that the operation of reversing the charger is performed at the end of one printing cycle. According to a third aspect of the present invention, the photoconductor drum and the charger are incorporated in one unit, and the toner remaining on the photoconductor drum is transferred to a paper after a toner image formed on the photoconductor drum is transferred to a developing device. It is characterized in that the unit is incorporated in an apparatus of a system that is reused by returning to the above.

As described above, by rotating the rotating brush charger in the reverse direction, the brush of the brush charger, which had been tilted in one direction during printing, is tilted in the opposite direction, and the bristle is operated. Fall can be corrected. Since the toner and the like adhering to the brush charger can be removed, the charging performance of the brush charger can be favorably maintained, and deterioration of copy image quality can be prevented. Further, since the brush charger is automatically reversed when the printing operation is completed, the user does not feel uncomfortable. 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 while scanning the original set on the platen, the image information can be read. The transmission operation 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 transmitting the scanning information of the original to the CCD 38 via the lens device 37, and converts the optical signal into an electric signal, which is transmitted to the image information processing section disposed on the main body frame. I do. In order to drive the full-rate carriage 31 and the half-rate carriage 33, in the present embodiment, the drive pulley 3 having a diameter set to 2: 1 is used.
5, 35a are coaxially arranged, and a mechanism is provided for moving the two carriages in conjunction with each other via belts 36, 36a wound around 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 transport unit on the control panel. In response to the signal, the full-rate carriage 31 of the scanning device 30 is stopped at a position corresponding to the platen 24, the half-rate carriage 33 is moved to the left end of the scanning unit frame 30, and the original is moved from the original tray 27 to the original. One by one U-shaped transport path 4
The document is conveyed within the platen 4, and the image of the document is read 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 55 of the developing unit 50 is disposed with respect to the photosensitive drum 62 provided on the photosensitive unit 60.
The transfer roller 17 is provided so as to sandwich the paper passage. Two units 5 constituting the process device 50
As described later, the reference numerals 1 and 60 are provided detachably from the upper part of the main body frame while being integrally assembled, and are fixed and held at the operation position with the intermediate lid 10 closed.

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 81, the transport roller device 16 is driven to feed 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 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 setting a thin layer of toner formed on the surface of the developing roller 55, and is a urethane resin sheet or a stainless steel plate member. It is configured as having spring properties. And, for the layer thickness regulating member 56, -300V to -500V
A bias voltage in a range of V, preferably around -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.

The photosensitive unit 60 arranged in combination with the developing unit 51 includes a unit frame 61.
Drum 62 supported on the surface, and a brush charger 65 such as a brush roller whose surface is formed by a flocked member or the like
Are provided. Then, the 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. Further, the writing unit 70 is configured by an LED head array, and based on information from an image information output device,
The ED emits light to irradiate the photosensitive drum with light. The surface of the photoreceptor drum 62 is made of a grounded photoconductor, charged at −780 V by the brush charger 65, and irradiated with light from the writing unit 70.
That is, the potential of the portion of the image information corresponding to black becomes approximately -80 V, and a potential difference occurs between the light-irradiated portion and the non-irradiated portion (the portion corresponding to the white portion of the image information), thereby forming an electrostatic latent image corresponding to the image information. Is done.

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 In a photoconductor unit 60 provided in the process unit 50, as shown in FIG. 5, a brush member 66 and a brush charging device are disposed between a toner image transfer position and an image writing position with respect to a photoconductor drum 62. Devices 65 are sequentially arranged. The brush charger 65 is configured as a brush roller provided with a conductive flocking member with respect to a metal shaft, and after transferring a toner image to paper,
A new charging action is performed on the surface of the photosensitive drum. A memory removing brush 66 is provided upstream of the brush charger 65.
After the toner image is transferred to the paper, the toner remaining on the surface of the photoconductor drum is disturbed by the memory removal brush 66 and dispersed on the surface of the photoconductor drum. Is charged to the same potential as the surface of the photoreceptor drum by the action of the brush charger 65. Then, at a position where the photosensitive drum contacts the developing roller 55,
Transferred to the developing roller 55 side due to the potential difference between the two,
The apparatus is configured as a cleaner-less type apparatus by being mixed with toner newly supplied from the container and reused. A power supply is connected to the brush charger 65,
A DC voltage of -780 V is applied.

The photosensitive drum 62 and the brush charger 65
When a printing operation for forming a toner image on the photosensitive drum and transferring it to paper is performed, the photosensitive drum is driven by a potential applied to the brush charger 65 in a state where the photosensitive drum is driven together in the direction of arrow X in FIG. The function of charging the surface is performed. Therefore, at the position where the brush charger is pressed against the photosensitive drum, the bristles of the brush of the brush charger are strongly rubbed against the surface of the photosensitive drum, so that the brush falls in the rotating direction of the photosensitive drum. Added. Then, in order to correct the fall of the bristles of the brush of the brush charger, after the printing operation is finished, the brush charger 65 alone or the photosensitive drum 62 and the brush charger 65 are simultaneously rotated in the reverse direction ( The operation of driving in the direction of the arrow X1) is performed only for a predetermined time. Then, the brush charger is rubbed against the surface of the photoreceptor drum in the opposite direction, so that the brush of the brush charger has a function of correcting the fall of the bristles, and the function of bending the bristles in the opposite direction. Is performed at the same time as the action of brushing off the toner and the like that has entered the brush.

The example shown in FIG. 6 shows an example in which a scraper 67 is added to the brush charger 65 in addition to the example shown in FIG. 5, and the scraper 67 is, for example, a brush. Attached to the member supporting the member 66,
The tip of the scraper is provided so as to bite into the brush charger 65. The base of the scraper 67 can be attached to the unit frame 61 of the photoreceptor unit 60, and the scraper 67 can be arranged so that the tip of the scraper bites into the brush of the brush charger 65 by several mm. When the scraper 67 is provided, the surface of the rotating brush charger 65 is rubbed by the scraper, thereby performing an action of sweeping off toner, paper powder, and the like that have entered during the flocking. The plate member 67 disposed with respect to the brush charger 65 can be configured using a simple single plate-shaped member. In addition, a portion that comes into contact with the brush charger is plate-shaped. The base may be provided with a hole or the like having an arbitrary size.

In the example shown in FIG. 6, when the photosensitive drum 62 and the brush charger 65 are rotated in the direction of arrow X to perform a printing operation, the brush charger 65 is attached to the photosensitive drum. The sliding causes the hair of the brush charger to fall down to one side. Further, the brush charger 65 is rubbed against the scraper 67 during the rotation thereof, and the brush charger 65 has a function of sweeping off the toner and the like that has entered between the brush bristles. Will be encouraged. Therefore, in this embodiment, FIG.
As in the case of the above, after the printing operation has been completed, the brush charger is operated by simultaneously driving the photosensitive drum and the brush charger or reversely driving only the brush charger in the direction of arrow X1. The hair is forcibly bent in the direction opposite to the direction of the printing operation, and an operation for correcting the fall of the brush hair is performed.

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.

As shown in FIGS. 5 and 6, after the printing operation is completed, the image is transferred to the photoconductor drum and the brush charger arranged in the photoconductor unit at the same time or only the brush charger is reversed. A control program as shown in the timing chart of FIG. 7 can be set in the control device of the printing apparatus. In the timing chart, as the copy signal, a signal for setting an original on the image recording apparatus and starting the operation of the scanning apparatus is used, and after a predetermined time has elapsed from the input of the copy signal, the photosensitive drum and the brush charger are used. Starts rotating, and a voltage of a predetermined value is applied to the brush charger. Then, writing of an image to the photosensitive drum is started, a toner image is formed by the toner supplied from the developing device, and a predetermined number of copies are sequentially created.

When the copy creation operation is completed, it is confirmed that the copy creation operation has been completed by using a detection signal of the last original or a signal indicating that a plurality of copies have been made from one original. After the end signal is received, the photosensitive drum and the brush charger are driven to rotate in the reverse direction. The operation of applying a voltage to the brush charger is turned off at the end of the normal rotation operation, and the operation of charging the photosensitive drum is stopped at the time of reverse rotation. The operation of the reverse rotation drive includes:
After a predetermined time t, and the reverse operation is completed,
The copy signal is also turned off, and the image recording apparatus is put on standby until a signal for making the next copy is input.

In the timing chart shown in FIG. 7, the operation of rotating the photosensitive drum and the brush charger in the reverse direction is performed before the photosensitive drum and the brush charger are rotated in the normal direction. It is also possible to set to rotate in the reverse direction and then rotate in the forward direction. Then, immediately after the copy signal is inputted, even if a program for rotating the photosensitive drum and the brush charger in the reverse direction and then setting the program to perform the normal rotation is set in the control device, the operation by the reverse rotation of the brush charger is similarly performed. Will be done. Furthermore, the operation of rotating the photosensitive drum and the like in the normal and reverse directions can be performed twice at the start and end of the copy creation. Apart from the above embodiment,
In the present invention, the photoconductor drum can be configured to be capable of rotating only in the normal direction, and the brush charger can be configured to be capable of rotating in the normal and reverse directions. It is possible to reverse only the charger at an arbitrary timing. However, for the example of FIG. 7, a program is set to perform the reverse operation of the brush charger at the start of the copy creation or at the end of the copy creation operation. By doing so, it is possible to respond.

[0034]

In the apparatus according to the present invention, since the rotating brush charger is rotated in the opposite direction, the brush of the brush charger is tilted in one direction during printing by rotating the rotating brush charger in the opposite direction. The action of tilting the hair in the opposite direction is performed, so that hair fall can be corrected. Since the toner and the like adhering to the brush charger can be removed, the charging performance of the brush charger can be favorably maintained, and the deterioration of copy image quality can be prevented. Further, since the brush charger is automatically reversed when the printing operation is completed, the user does not feel uncomfortable. Further, by incorporating the unit of the present invention into a cleaner-less type apparatus, the features of the image recording apparatus can be effectively utilized, and the action of charging the photosensitive drum can be performed under favorable conditions, so that copying of the image can be performed. Good image quality can be maintained.

[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.

FIG. 7 is a timing chart showing the operation of reverse rotation driving of the brush charger in the present invention.

[Explanation of symbols]

1 image recording device, 2 body frame, 3
Paper cassette, 7 discharge tray, 10 intermediate lid,
11 fulcrum, 13 paper feed roller, 14 paper transport path, 15 and 16 transport roller device, 17 transfer roller, 18 fixing device, 20 scanning unit frame, 21 fulcrum, 23 and 24 platen, 25
Upper opening frame, 26 Platen cover, 2
7 Document tray, 28 Document output tray, 30
Scanning device, 31 Full rate carriage, 33
Half-rate carriage, 35 drive pulley,
37 lens, 38 CCD, 40 document feeder, 41 opening / closing frame, 50 process device,
51 developing unit, 55 developing roller, 6
0 Photoconductor unit, 63 Drum shaft, 65
Brush charger, 66 brush member, 67 scraper, 70 writing device.

Claims (3)

[Claims] 1. An image recording apparatus in which a charging device is arranged on a photosensitive drum and uniform charging is performed before irradiating the photosensitive drum with image light, wherein the charging device comprises a brush charger. An image recording apparatus wherein the photosensitive drum is pressed and rotated in the same direction, and the charger is driven for a predetermined time in a direction opposite to the rotation direction during printing during a time period other than the printing operation. . 2. The method according to claim 1, wherein the operation of reversing the charger is performed at the end of one printing cycle.
The image recording apparatus according to claim 1. 3. A photoconductor drum and a charger are incorporated in a single unit, and after a toner image formed on the photoconductor drum is transferred to a sheet, toner remaining on the photoconductor drum is returned to a developing device. The image recording apparatus according to claim 1, wherein the unit is incorporated in an apparatus of a reusable type.