JP3338166B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus which is mainly applied as a printer, a copying machine, a facsimile or a multifunction machine thereof, and which can selectively feed recording materials of different sizes. The present invention relates to an invention applied as an image forming apparatus provided with a paper feeding unit.

[0002]

2. Description of the Related Art Conventionally, in printers and copiers,
A4 A manual paper feed unit is provided separately from the paper cassette in which standard paper is stored, so that postcards and recording paper of a type different from the recording paper stored in the paper cassette can be printed. It is configured to enable copying. Further, in order to reduce the size and flattening of the image forming apparatus, a single and flat sheet feeding cassette to be housed in the main body of the apparatus is provided, and an optional feeding cassette for storing recording materials of other sizes and / or a large number of recording materials is provided. There is also a system in which a paper unit can be mounted according to a user's request. Further, an apparatus has been proposed in which the sheet cassette is formed of a universal cassette so that the size of the recording material stored in the recording material storage section of the apparatus main body can be changed.

On the other hand, in a photosensitive drum for transferring a toner image onto the recording material, a toner image is formed in accordance with the size of a recording sheet to be fed. When a recording material having a different size from the paper portion is selectively fed to the transfer position of the photosensitive drum, the photosensitive material must be detected in advance by the paper feeding unit before the photosensitive material is detected. In some cases, the size of the toner image printed on the drum and the size of the recording material may differ. In such a case, the remaining toner image after printing adheres to the recording material from the photosensitive drum to the transfer roller side, and the next recording is performed. This not only contaminates the back surface of the material, but also damages the photosensitive drum.

In order to solve such a drawback, a size detection sensor for detecting the size of the recording material is provided for each size. However, such a configuration complicates the configuration and guides the sensor signal to a substrate on the apparatus body side. And other harnesses are routed inside the apparatus, and the harnesses and the like may be damaged. Further, a sensor for detecting the absence of paper of the recording material must also be attached to the cassette on the option unit side together with the paper feed cassette, so that the configuration is complicated and the wiring of the harness is further complicated.

Japanese Utility Model Application No. 4-11 filed by the present applicant
As shown by reference numeral 567, a sheet cassette is configured to be able to be stored in a cassette storage section of the apparatus main body, and an optional sheet supply unit is disposed on the apparatus bottom side on the lower side of the cassette, and a recording material storage section of the sheet cassette is provided. A vertical guide path for guiding the recording material fed from the optional unit to the feed roller or the registration roller entrance end while inverting the recording material is provided between the front and rear walls. In such a vertical guide path, an air gap between conveying ribs forming the guide path is set as wide as possible in order to minimize the sheet feeding resistance when performing reverse sheet feeding of the recording material. With such a configuration, when the recording material is fed, the recording material falls or flutters, and skew or the like is likely to occur.

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of the prior art, the present invention is to register a recording material having a different size selectively using a universal cassette or a manual paper feed mechanism or from a plurality of paper feed units. Even in a device that guides the rollers to form an image, a size detection sensor is not provided in each paper feeding unit, and the remaining toner image after printing on the recording material is transferred from the photosensitive drum to the transfer roller with only one detection sensor. The purpose of the present invention is to prevent the toner from adhering to the side, prevent contamination of the back surface of the recording material, and prevent the photosensitive drum from being damaged. Another object of the present invention is to simplify the configuration and to eliminate the possibility of breakage caused by wiring of the harness.

Another object of the present invention is to provide an apparatus in which a paper feed cassette is configured to be housed in a cassette housing section of an apparatus main body and an optional unit is provided on the apparatus bottom side on the lower side of the cassette. An object of the present invention is to provide an image forming apparatus which is configured to be able to detect the absence of paper in both units by an absence sensor, thereby reducing the number of parts and simplifying the construction.

[0008] Another object of the present invention from the production, and even in the simple structure, yet is to be user-friendliness providing highly preferred image forming apparatus.

[0009]

The present invention does not detect the size of the recording material as in the prior art described above. The present invention relates to a method for detecting the size of a plurality of paper feed paths as shown in FIG. A trailing edge detection sensor 46 for the recording material is disposed at the entrance side of the roller 4 to detect the trailing edge of the fed recording material, and after the trailing edge of the recording material is detected, charging and exposure of the photosensitive drum 6 are stopped. This prevents formation of a toner image beyond the rear end of the recording material and prevents charging fatigue of the photosensitive drum 6. That is, the present invention is previously fed recording material size is unknown image forming apparatus as images forming device universal cassette or manual paper feed mechanism, or the sheet feed cassette,
Applied to an apparatus having a plurality of paper feeding units such as a manual paper feeding unit and an optional paper feeding unit, and detects a trailing edge of a recording material at an entrance side of the registration roller 4 after at least a plurality of paper feeding paths are gathered. Sensor 46, and the rear end detection sensor 46
The first feature is that the feeding distance L from the charging roller to the transfer position along the rotation direction of the photosensitive drum 6 is set to be larger than the distance from the charging position to the transfer position (charging distance P) along the rotation direction of the photosensitive drum 6. It is assumed that.

According to such a technical means, a paper feed detecting sensor is provided.
Is not provided for each paper feeding unit, and the
Paper feed detection is possible only with the rear end detection sensor
Simplified configuration for sufficient one sensor is not necessary to provide a sensor for each sheet feeding unit of the respective through and Turkey, Thus also can eliminate the risk of lead or the like of the harness occurs. According to this technical means, the feeding distance L is set to be larger than the charging distance P, and the feeding distance L is set by the detection sensor.
After detecting the trailing edge of the recording material at the registration roller entrance side, the photosensitive drum
A part to transfer to recording material by stopping charging of the system
The charging of the photosensitive drum is performed only for the portion, and the charging of the photosensitive drum 6 is stopped after the trailing edge detection, so that the photosensitive drum 6 is charged only at a portion to be transferred to the recording material. can be damage to 6 can be prevented.

[0011] Further since the distance from the exposure position to the transfer position in the direction of drum rotation downstream side of the charging position (exposure distance R) is smaller than naturally feeding distance L, the sensor
After the trailing edge of the recording material is detected
Ram charging, image writing, and developing via of developing unit
By sequentially stopping the recording material, exposure / development can be performed only on the portion to be transferred to the recording material, so that the toner image protruding from the rear end of the recording material does not adhere to the transfer roller 5 side, and the back surface of the recording material Pollution can be prevented. When the photosensitive layer of the photosensitive drum 6 is formed of amorphous silicon, the feed distance L> the exposure distance R may be set without considering the fatigue of the drum.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention, but are merely illustrative examples. Not just.

FIG. 3 shows a schematic internal configuration of a page printer according to an embodiment of the present invention. The paper cassette storage space 1A, board mounting space 1B,
It is divided into three process unit mounting spaces 1C, and a paper feed opening 50
d2A, and connected to the paper feed opening 50d2A in FIG.
The optional paper feed unit 60 (see FIG. 1) as shown in FIG.

The process unit mounting space 1C extends along the upper surface of a partition wall 1D which partitions the board mounting space 1B.
A registration guide path 19, an intermediate sheet feeding roller 18 in which the entrance end of the guide path 19 is recessed in a rectangular shape and is rotatably supported by the recess 19 a, a registration roller pair 4, a transfer roller 5
And a photoreceptor drum 6 and a fixing unit 7. On the other hand, around the photoreceptor drum 6, a cleaner 11, a particle charging unit 12, an LED unit 13, along a drum rotation direction (counterclockwise). And a developing unit 14. The photosensitive drum 6 from which the residual toner has been removed by the cleaner 11 is uniformly charged by the particle charging unit 12, and the exposure latent image corresponding to the image information is emitted by the LED unit 13. Writing to the developing unit 1
After the latent image is visualized by 4 to form a toner image, the latent image is transferred to the recording paper side by the transfer roller 5.

A manual switching lever 49 is provided at the exit end of the intermediate transfer roller 8, and the switching operation of the switching lever 49 causes the upper surface of the intermediate transfer roller 8 to be placed on a discharge tray 41 provided at the rear end of the apparatus. The paper is ejected. Reference numeral 16 denotes a display panel mounting portion provided on the front wall side of the apparatus.

As shown in FIG. 1, a recording paper trailing end detection sensor 46 having an actuator 46a that swings by passing the recording paper is provided in the registration guide path 19 on the entrance side of the registration roller 4. The feeding distance L from the trailing edge detection sensor 46 to the transfer position of the transfer roller 5 beyond the registration roller 4 is set to the charging roller (magnet) of the particle charging unit 12 along the rotation direction (arrow direction) of the photosensitive drum 6. The distance (charging distance P) from the charging position of the charging sleeve in which the assembly is inserted to the transfer roller 5 is set to be larger.

With the above configuration, the distance (exposure distance R) from the exposure position downstream of the charging position in the drum rotation direction to the transfer position (exposure distance R) is naturally smaller than the feeding distance L.

According to this embodiment, a recording sheet selectively fed from the manual sheet feeding unit 34, the sheet feeding cassette 2, or the sheet feeding unit 60 shown in FIG. After the paper passes through the intermediate paper feed roller 18 and the registration guide path 19 and waits at the entrance end of the registration roller 4, the photosensitive drum 6 is charged by the particle charging unit 12.
After the entire surface is charged, exposure is performed by the LED unit 13, development is further performed by the development unit 14, and the registration roller 4 is rotated in synchronization with the start end of the toner image carried on the photosensitive drum 6. 5, the toner image is transferred, and the image is fixed by passing the fixing roller pair 7a of the fixing unit 7 therethrough. Thereafter, the image forming apparatus is transferred via the intermediate discharge roller 8, the discharge guide 40, and the discharge roller pair 9. The paper is discharged to the paper discharge tray unit 10 on the upper surface side.

When the trailing edge of the recording paper passes through the entrance side of the registration roller 4 during the image forming operation, the trailing edge detection sensor 46 detects this by swinging of the actuator, and
The detection signal is transmitted to a control circuit (not shown) provided on the substrate 3. On the control circuit side, based on the detection signal, the charging bias of the particle charging unit 12 and the LED unit 13
Image writing and the developing bias of the developing unit 14 are sequentially stopped, and the end of the toner image carried on the photosensitive drum 6 is controlled so as not to exceed the rear end of the recording paper. Of course, in this case, when the photosensitive layer of the photosensitive drum 6 is formed of amorphous silicon, the feeding distance L> the exposure distance R is set without much consideration of the drum fatigue.
Only the image writing of the LED unit 13 may be stopped while the charging of the particle charging unit 12 is continued based on the detection signal.

On the other hand, the board mounting space 1B allows the board 3 to be set on legs 3A provided on the partition wall 1E located on the lower surface side, and the board 3 is moved along a guide 3B provided on the side wall. It can be pulled out from the right rear wall.

The cassette accommodating space 1A has a device length corresponding to the A4 size of the present apparatus, while the paper cassette 2 is a universal cassette capable of supporting the B4 or letter size. When the rear wall of the apparatus main body 1 is opened together with the front wall into which the paper feed cassette 2 is inserted and removed, and a B4 or letter size is stored, a part of the rear end regulating member from the rear end of the cassette 2 is formed. A vertical regulating plate 21 for regulating the trailing edge of the recording paper is configured to be extendable.

A paper feed roller 17 is provided at the upper front end of the cassette storage space 1A, and the recording paper stored in the recording paper storage portion of the cassette via the mounting plate 26 urged upward by a coil spring 27. Are configured to be able to contact the peripheral surface of the paper feed roller 17.

Next, the overall configuration of the paper feed cassette 2 will be described with reference to FIG. In FIG. 4, reference numeral 20 denotes a cassette base functioning as a recording paper storage section, which is formed in a flat shape without a vertical wall at the rear end side, and is position-restricted by a position restriction portion 22 provided at the rear end on the base 20 side. End regulating member 2 which advances and retreats along the cassette longitudinal direction while being moved
1 is attached, and the rear end regulating portion 211 that moves by the forward / backward operation of the rear end regulating member 21 is positioned on the rear end of the base 20 to regulate the position of the A4 size. By extending outward from the end further, the rear end regulation of B4 or letter size is performed. On the other hand, by moving the rear end regulation portion 211 to the inside of the base 20, B5 or postcard size smaller than A4 is set. The rear end of the length can be regulated.

Reference numeral 23 denotes a pair of width regulating plates, which are symmetrically moved in the width direction by a gear 24 pivotally supported at the center in the short direction of the base 20 and a rack meshing with the gear 24. The width of the recording paper of the size can be regulated. On the base 20 on the front side of the rack 25 of the width regulating plate 23, a flat and flat convex mounting plate 26 is pivotally supported so as to swing upward about a fulcrum 26 a provided near the rack 25.

Coil springs 27 are interposed on the left and right sides of the base between the mounting plate 26 and the base 20 in the lateral direction of the base to urge the mounting plate 26 upward. The mounting plate 26 extends to the position of the base side wall 20A on the left and right sides, and a triangular projection 43 facing the rib 42 is erected at the extending position. In addition, a rectangular claw portion 29 extends toward the front side at the front corner of the mounting plate 26, and engages with the claw portion 29 on the front end side of the base, thereby mounting the mounting plate. An engaging claw 36 is provided to be laid down along the base 20 against the urging force.

The engaging pawl 36 is connected to the base side wall 20.
A lock lever 30 provided on the outer wall surface side is configured so as to be swingable integrally therewith, while a lock pin 40 engaging with a lock lever 30 described later is provided on a main body side wall below the paper feed roller 17.
Project inward.

By pulling out the sheet cassette 2, the triangular projection 43 of the sheet cassette 26 is
When the mounting plate 26 is pressed downward against the elastic force of the coil spring 27 when crossing the second side, the engaging claws 36 of the lock lever 30 shown in FIG.
Are engaged. Therefore, the mounting plate 26 is laid down on the side of the base 20 against the elastic force of the coil spring 27 by the engagement, so that the recording paper can be easily loaded. When this is done, the tip of the cassette lock lever 30 is pressed by the body side pin 40 and engages with the pin 40 while swinging downward against the spring 51 biased against the lock lever 30, and Swinging downwards causes the engagement claw portion 36 to retreat from the engagement position, and by disengaging from the engagement claw 36,
Similarly to the above, the recording paper placed on the loading plate 26 is brought into contact with the peripheral surface of the paper feed roller 17, and the lock lever 30 urged upward by the spring 51 is engaged with the main body side pin 40. In this case, the positioning is locked, and the friction pressure of the friction plate 34 is always constant. Since such a point is not the gist of the present invention, detailed description will be omitted.

Reference numeral 32 denotes a front wall which functions as a cassette drawer. The front wall 32 stands up to the lower surface position of the display panel mounting portion 16, and a manual paper feed mechanism 34 is fitted into a slit opening 32A on the upper surface. Manual feed mechanism 34
Is composed of a manual paper feed tray 341 to which a pair of width regulating plates 342 moving in the width direction is attached. The paper feed tray 341 is pulled upward from the slit opening 32A, and is tilted down by a predetermined angle toward the front side. Functions as a manual feed surface. On the other hand, the inner wall side of the cassette front wall 32 is erected to a position facing the entrance end of the registration guide path 19, and the recording material fed by the paper feed roller 17 is placed at the entrance end of the registration guide path 19. A plurality of rib-shaped guide walls 47 for guiding are formed. In addition, a reversing paper feed path 50 is formed along the guide rib 47 and between the recording paper storage unit.

Hereinafter, these will be described in detail. The reversing sheet feeding path 50 has a starting end on the sheet feeding opening 50 of the optional sheet feeding unit 60 disposed on the bottom side of the apparatus main body 1.
The recording material fed from the paper feed cassette 2 and the optional paper feed unit 60 extends to the position d.
9 is fed toward the inlet end side. A plurality of rib-shaped guide walls 47 are formed at appropriate intervals in the width direction on the inner wall side of the cassette front wall 32 facing the reversing sheet supply path 50, and the guide walls 47 are supplied from the sheet cassette 2. A predetermined portion (first guide wall portion 47a) with which the leading end of the recording material fed by the paper roller abuts is formed in a substantially arcuate shape to form a wide curvature path, and further, the first guide wall portion 47a is formed. The second guide wall portion 47b further reaching the registration guide path 19 is formed so as to be substantially linearly inclined so as to gradually become narrower to the entrance end of the registration guide path 19,
On the other hand, the third guide wall portion 47c extending from the position of the paper feed opening 50d to the first guide wall portion 47a is formed so as to have a bulge like a spindle.
The path 50c from 0 is formed so as to gradually become narrower. Then, the sheet feeding roller 17 is directly opposed to the first guide wall portion 47a, and the peripheral surface of the sheet feeding roller 17 is configured to form a part of a wide path path 50a. In this case, the path 50a can be made even larger, and the peripheral surface of the paper feed roller 17 can also function as a drive conveyance peripheral surface in the path.

The paper feeding unit 60 is urged upward by a spring 62 as is well known, and a loading plate 61 on which a large number of recording papers are loaded, and a paper feeding support shaft supported at an upper position on the front side of the loading plate 61. A unit main body 60A including a paper roller 63, a paper feed guide 64 for guiding the recording paper fed by the paper feed roller 63 to the paper feed opening 50d of the apparatus main body 1;
A housing 60 that accommodates 0A so that it can be pulled out in the direction of the arrow.
B.

A pair of actuators 55 and 56 are provided on the side surface of the housing 60B, which is located above the mounting plate 61 of the paper feed roller unit 60 and is out of the recording material mounting area.
Detection piece 55 on the free end side of actuators 55 and 56
One paper absence detection sensor 57 is arranged at the gathering position of b and 56b. The paper absence detection sensor 57 is formed in a U-shaped cross section having a concave portion 57a into which each of the actuators 56 can enter, and a light receiving element 571 and a light emitting element 572 are provided on both opposing side surfaces. 55b, 56
When b enters the concave portion 57a, the sensor signal is turned off and it is determined that there is no paper.

One actuator 56 has a swinging piece 56a located on the upper side extended from a window 58 provided at the bottom of the apparatus main body 1 so as to contact the bottom surface of the mounting plate 26,
When the recording paper placed on the mounting plate 26 rises to an empty position, the lower-side detection piece 56b is moved to the position where the recording paper placed on the mounting plate 26 becomes empty.
Is supported on the support shaft 56c so as to block the light receiving surface of the support shaft 56c. The other actuator 55 extends the swinging piece 55a located on the lower side so as to come into contact with the upper surface position of the paper supply unit 60 side mounting plate 61 separated from the recording paper storage portion, and raises the mounting plate 61. When the recording paper placed on the loading plate 61 rises to a position where the recording paper is empty, the upper detection piece 55b is pivoted so as to block the light receiving surface of the paper absence detection sensor 57 when the recording paper is raised. 55c.

As a result, as shown in FIG. 2A, detecting pieces 55b and 56 of actuators 55 and 56 for detecting the swing of the paper feed unit 60 or the paper feed cassette 2.
When b enters, light reception to the light receiving element 571 side is blocked, and it can be determined that there is no paper. Also, as shown in FIG. 2B, instead of the light emitting element and the light receiving element, proximity switches SW1 and SW2 are arranged on a U-shaped wall.
Since the a and 56a sides are made of a metal plate, the entry of the corresponding actuator 56 can be detected by each of the U-shaped walls, and the paper of any paper feeding unit (the paper feeding unit 60 or the paper feeding cassette 2) can be detected. No proximity switch SW1,
It is possible to detect with high accuracy by the sensor output from SW2.

Next, the sheet feeding operation from the sheet feeding cassette 2 and the sheet feeding unit 60 will be described. First, after a paper presence signal is output from the paper absence sensor 57, when the paper feed roller 17 rotates to feed paper from the paper feed cassette 2,
After the leading end of the recording paper comes into contact with the first guide wall portion 47a as the paper feed roller 17 rotates, the guide wall 47
a is forcibly bent upward along the arcuate surface of a, but at this time, the path 50a of the curved portion is formed wide,
In addition, the peripheral surface of the paper feed roller 17 also functions as a peripheral surface of the drive path in the path 50a, so that the paper feed resistance is small and the paper can be fed smoothly. Thereafter, the recording paper is guided to the entrance end of the registration guide path 19. At this time, the exit path 50b of the path path 50 is formed so as to be gradually narrowed by the second guide wall portion 47c. As a result, it is possible to accurately enter the registration guide path 19 in a state where both ends are regulated by the paper feed roller 17 and the second guide wall portion 47b with the first guide wall portion 47a interposed therebetween. The conveyance from the optional unit 60 also passes through the paper feed guide 64 by the rotation of the paper feed roller 17 of the unit 60, and moves vertically from the position of the paper feed opening 50 d to the reverse path 5.
0, and then enter the wide pass path 50a along the bulged guide wall portion 47c with the play of the recording paper suppressed, and the recording material is removed from the guide wall 47.
Is guided to the entrance end of the registration guide path 19 while being forcibly inverted in the wide path path 50a while holding at the narrow portion of the first guide wall portion 47a. Third and second guide wall portions 47b to be
Registration guide path 1 with both ends regulated by 47c
9 can be entered.

[0035]

As described above, according to the present invention, an apparatus for forming an image by using a universal cassette or a manual sheet feeding mechanism or selectively guiding recording materials having different sizes to a registration roller from a plurality of sheet feeding units is provided. Even if there is no size detection sensor in each paper feeding unit, only one detection sensor prevents the remaining toner image after printing on the recording material from adhering from the photosensitive drum to the transfer roller side, It is possible to effectively prevent contamination of the back surface of the recording material and effectively prevent damage to the photosensitive drum. Further, according to the present invention, since there is only one sensor, the structure can be simplified and the possibility of breakage caused by wiring of the harness can be eliminated. Further , according to the present invention, the occurrence of a jam on the reverse sheet feeding path is suppressed, and even if the jam occurs, the processing is extremely easy. Further, according to the present invention, it is possible to obtain an image forming apparatus in which the structure is simplified from the viewpoint of manufacturing and the user's usability is extremely favorable. And so on.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view of a main part on a front wall side of an image forming apparatus equipped with a sheet feeding unit according to an embodiment of the present invention.

FIG. 2 is an operation diagram for detecting the presence / absence of a sheet of recording material in a sheet feeding unit and a sheet feeding cassette;

FIG. 3 shows an overall configuration of an image forming apparatus according to an embodiment of the present invention.

FIG. 4 is an overall plan view of a sheet cassette.

FIG. 5 is an enlarged plan view of a main part of FIG. 4, particularly showing the shape of the front side of the cassette;

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 apparatus main body 2 paper feed cassette 4 registration roller 5 transfer roller 6 photosensitive drum 12 charging unit 17 paper feed roller 19 registration guide path 20 recording material storage section 32 cassette front wall 34 manual feed section 46 rear end detection sensor 47 guide wall 47a First guide wall portion 47b Second guide wall portion 47c Third guide wall portion 50 Paper feed path 50a Wide path 50d Paper feed openings 55, 56 Actuator 57 No paper detection sensor 60 Paper feed unit

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-57-8554 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/00

Claims (2)

(57) [Claims] A plurality of paper feed units having different sizes;
Device that guides a recording material to a registration roller to form an image
The registration roller after at least a plurality of paper feed paths are assembled
A rear end detection sensor for the recording material is arranged on the entrance side to detect the rear end.
Feeding from the sensor to the transfer position beyond the registration roller
Transfer distance from charged position along photoconductor drum rotation direction
Set it larger than the distance to the position and, The detection sensor detects the recording material at the registration roller entrance side.
By stopping charging of the photosensitive drum after detecting the trailing edge,
The photosensitive drum is charged only to the part to be transferred to the recording material.
That Image forming apparatus characterized by the following. 2. A paper feeding apparatus according to claim 2, wherein said plurality of paper feed units have different sizes.
Device that guides a recording material to a registration roller to form an image
The registration roller after at least a plurality of paper feed paths are assembled
A rear end detection sensor for the recording material is arranged on the entrance side to detect the rear end.
Feeding from the sensor to the transfer position beyond the registration roller
Transfer distance from charged position along photoconductor drum rotation direction
Set it larger than the distance to the position and,  The detection sensor detects the recording material at the registration roller entrance side.
Charge of photosensitive drum after trailing edge detection, Image writing, and development
Stop the development bias of each knit sequentiallyFeatures
Image forming apparatus.