JP3086394B2 - Copier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine capable of copying a large-sized document.

[0002]

2. Description of the Related Art An original is illuminated and scanned, an electrostatic latent image is formed on a photoreceptor by reflected light from the original, the electrostatic latent image is visualized as a toner image, and the toner image is formed on a copy sheet. 2. Description of the Related Art An electrophotographic copying machine adapted to heat and fix is widely used. As such a copying machine, there is provided a copying machine capable of copying a document of a large size, for example, Japanese Industrial Standards A row 0 (hereinafter referred to as "A0 version").

A copying machine capable of copying a large-sized document is provided with a reading mechanism capable of reading a large-sized document, and a transport mechanism for transporting a large-sized copy sheet corresponding to the document. Have.

[0004]

When a large-sized copy sheet is conveyed, the copy sheet is obliquely shifted during conveyance, or is copied when moving from one conveyance roller to the next conveyance roller. In some cases, the image was distorted. SUMMARY OF THE INVENTION It is an object of the present invention to provide a copying machine capable of favorably conveying a large-sized copy sheet.

[0005]

SUMMARY OF THE INVENTION The present invention, in one aspect, includes a photoreceptor, an image to be copied is formed on the photoreceptor by electrophotography, and the formed image is transferred to a given copy sheet. A forming section, a transport path for guiding a copy sheet to the image forming section, and a transport provided at a position near the image forming section in the transport path, for supplying the copy sheet to the image forming section at a predetermined transport speed. Roller, a registration roller in the conveyance path, as viewed in the direction of conveyance of the copy sheet, and a registration roller provided upstream of the position of the conveyance roller, and a registration roller in the conveyance path, as viewed in the direction of conveyance of the copy sheet. And a sheet end detecting means provided upstream of the arrangement position of the sheet. When the image forming unit starts transferring an image to the leading end of the copy sheet, the trailing end of the copy sheet is a sheet end detecting means. Transport than A copying machine that performs copying on a longitudinal copy sheet existing on the upstream side in the direction, and further, in a state where the sheet edge detection unit does not detect an edge of the copy sheet being transported on the transport path, conveying rollers and the resist constantly predetermined tension to a copy sheet between the rollers pressing forte during transport
In order to prevent the copy sheet from being shifted obliquely, the registration roller is moved to the first speed lower than the peripheral speed of the transport roller by a predetermined speed.
In response to the sheet edge detecting means detecting the end of the copy sheet being conveyed along the conveyance path, the tension applied to the copy sheet between the conveyance roller and the registration roller is increased. Register driving control means for increasing the registration roller from a first peripheral speed to a second peripheral speed higher by a predetermined speed than the peripheral speed of the transport roller so that the registration roller is not smoothed out. And

In another aspect of the present invention, a roll sheet drawn from a roll body formed by winding a long sheet or a cut sheet cut to a predetermined size is used as a copy sheet. In a copying machine, an image forming section including a photoreceptor, forming an image to be copied on the photoreceptor by electrophotography, transferring the formed image to a given copy sheet, and guiding a roll sheet to the image forming section And a transport roller provided at a position near the image forming unit in the vicinity of the roll sheet transport path and for feeding the sheet to the image forming unit at a predetermined transport speed, and cut into a predetermined size. For guiding the cut sheet, the leading end of the path is joined to the roll sheet transport path so as to guide the cut sheet to the transport roller. A cut sheet conveyance path having a cut sheet insertion opening at the rear end of the path, a registration roller provided in the cut sheet conveyance path, and a registration roller as viewed in the cut sheet conveyance direction in the cut sheet conveyance path. Sheet edge detecting means provided upstream of the disposition position of the sheet, and in a state where the sheet edge detecting means has not detected the end of the cut sheet being conveyed along the cut sheet conveying path, the conveying roller and the resist copy sheet is oblique in pressurized forte conveying constantly predetermined tension to the cut sheet between the rollers
The register roller is rotated at a first peripheral speed that is lower than the peripheral speed of the transport roller by a predetermined speed so that the sheet edge detecting unit detects the cut sheet being transported along the cut sheet transport path. In response to the detection of the end portion, the registration roller is moved from the first peripheral speed to the peripheral speed of the transport roller so that the tension applied to the cut sheet between the transport roller and the registration roller becomes smooth. Register driving control means for increasing the speed to a second peripheral speed higher than the predetermined peripheral speed by a predetermined speed.

[0007]

According to the present invention, it is possible to prevent skew of a copy sheet supplied from a registration roller to a transport roller (the copy sheet is shifted obliquely with respect to the transport direction). Further, it is possible to eliminate a sudden load change occurring in the transport roller due to a change in the tension of the copy sheet caused when the trailing edge of the copy sheet leaves the registration roller. As a result, the image transferred to the copy sheet can be prevented from being disturbed.

That is, while the copy sheet is being conveyed from the registration roller to the conveyance roller, a predetermined tension is applied to prevent skew. With this tension applied, the copy sheet suddenly loses tension as the trailing edge of the copy sheet leaves the registration roller. Therefore, the load of the transport roller fluctuates, and at that time, the image being transferred to the copy sheet may be disturbed.

Therefore, just before the trailing edge of the copy sheet leaves the registration roller, the peripheral speed of the registration roller is increased so that the tension applied to the copy sheet becomes smooth. As a result, when the trailing edge of the copy sheet leaves the registration roller, the load on the transport roller does not fluctuate, and the formed image is not disturbed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments will be described below in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view schematically illustrating an internal configuration of a copying machine according to an embodiment of the present invention, FIG. 2 is a perspective view illustrating an external configuration, and FIG. 3 is a perspective view illustrating the external appearance of the copying machine during copying. FIG. This copying machine is for obtaining a copy image of a large size original such as A0 size. In this copying machine, while the original is being conveyed, the surface of the original is illuminated and scanned by an optical system fixedly arranged, and an image is formed based on the illuminated scanning.

Referring to FIG. 1, a copying machine main body 1 is provided with caster wheels 2 at a bottom portion so that it can move freely. Referring to FIG. 1 to FIG.
A document transport unit 10 for transporting the document 9 along a document transport path 41 formed on the upper surface of the copying machine body 1
Is provided. A discharge port 54 from which the sheet on which the toner image is transferred is discharged is opened in the front surface 1a of the copying machine body 1. The sheet discharged from the discharge port 54 is
As shown in FIG. 3, while being guided by the guide member 91, the distal end of the copier body 1 is dropped with its tip downward, and is sequentially accommodated in the pocket 92 formed by the front cover 5 along the front surface 1a of the copying machine main body 1 through the introduction opening 93. It has become.
At the end of the upper surface of the copying machine body 1, an operation unit 100 provided with switches, keys, and the like for performing various settings related to copying is provided.

Referring to FIG. 1, the lower part of the copying machine main body 1 from the center in the height direction is provided with three upper and lower roll sheets 4A, 4B and 4C wound in a roll shape. Is housed. These roll sheets 4A, 4B, 4C
They are wound on supply reels 51, 52, 53, respectively. Examples of the types of the roll sheets 4A, 4B, 4C include plain paper, film, and tracing paper. Also, at the center of the copying machine body 1,
For example, a bypass conveyance path D4 is provided for supplying cut sheets, such as A0 size to A4 size, cut to a predetermined length in advance through the manual paper feed unit 30 on the front surface 1a of the copying machine body 1.

The upper roll sheet 4A includes the supply reel 51, the paper feed roller 61, and the conveyed roll sheet 4A.
A first leading edge detection switch 71 that detects the leading edge of the sheet, a transport roller 62, a cutter mechanism 80, a transport roller 63, a second leading edge detection switch 72 that detects the leading edge of each of the conveyed sheets 4A, 4B, 4C, and 4D. And a first transport path D1 to the photosensitive drum 20 via the transport rollers 33 in order.
Conveyed along.

The middle roll sheet 4B is supplied with a supply reel 5
2. Paper feed roller 64, third leading edge detection switch 73 for detecting the leading edge of rolled sheet 4B being transported, transport roller 62, cutter mechanism 80, transport roller 63, second leading edge detection switch 72, and transport roller 33 Sequentially through
The sheet is transported along a second transport path D2 that reaches the photosensitive drum 20. The path after the transport roller 62 is common to the first transport path D1.

The lower roll sheet 4C includes a supply reel 5
3. Paper feed roller 65, fourth leading edge detection switch 74 for detecting the leading edge of rolled sheet 4B being transported, transport roller 62, cutter mechanism 80, transport roller 63, second leading edge detection switch 72, and transport roller 33 Sequentially through
The sheet is conveyed along a third conveyance path D3 that reaches the photosensitive drum 20. The path after the transport roller 62 is common to the first transport path D1.

The bypass conveying path D4 is provided with a fifth leading edge detection switch 75 for detecting the leading edge of the cut sheet 4D introduced from the manual sheet feeding section 30, and a sliding contact plate (not shown). Separating roller 3 that separates cut sheets by sliding contact (separates one by one)
2. A path leading to the photosensitive drum 20 via the sixth leading edge detection switch 76 for detecting the leading edge of the cut sheet to be transported, the registration roller 39, the second leading edge detection switch 72, and the transport roller 33 in order. is there. The path after the second leading edge detection switch 72 on the bypass conveyance path D4 is common to the first conveyance path D1.

The above-mentioned cutter mechanism 80 cuts the roll sheets 4A to 4C between the long fixed blade 81 extending in the direction perpendicular to the conveying direction of the roll sheets 4A to 4C and the fixed blade 81. And a rotary blade 82 that performs the rotation. The document conveying section 10 sets the conveying direction to the forward direction R1 or the reverse direction R
2, and the original 9 is conveyed. The image forming operation is performed when the document is transported in the forward direction R1. When multiple copies are made from the same original,
The document transport unit 10 transports the document 9 by alternately switching the transport direction between a forward direction R1 and a reverse direction R2. On the upper surface of the copying machine main body 1, the above-described document conveying path 41 is formed upstream of the document conveying section 10 in the forward direction R <b> 1 to a position protruding from the upper surface of the copying machine main body 1.

The document transport section 10 includes a first document edge detecting switch 11, a first transport roller 12, a second document edge detecting switch 16, a second transport roller 14, And the third transport roller 15 are sequentially arranged. The first conveyance roller 12 starts to be driven when the first document end detection switch 11 is turned on from off and detects the leading end of the document 9 (the end on the downstream side in the forward direction R1). The second transport roller 14 is provided at a position facing the transparent plate 13 for slit exposure of the original 9, and brings the original 9 into close contact with the transparent plate 13. The third transport roller 15 discharges the exposed document 9.

The second document end detection switch 16
Is switched from off to on when the original 9 is conveyed in the forward direction R1, so that the original 9
Detect the tip of This second document end detection switch 16
Is turned on, conveyance of the roll sheet 4A, 4B or 4C (hereinafter, the roll sheet 4A, 4B or 4C conveyed for copying is simply referred to as "roll sheet 4") is started, and the As a result, the conveyance of the document and the roll sheet 4 is synchronized.

Further, the first document end detection switch 11
Is switched from on to off when the original 9 is conveyed in the forward direction R1, so that the original 9
Detect the rear end of At a predetermined timing after a lapse of a predetermined time from the timing of this detection, the cutter mechanism 80 is driven, and the roll sheet 4 is cut. In the present embodiment, the corona discharger 2 for transfer is
4 (transfer position 20b), the length of the transport path of the roll sheet 4 from the first original edge detection switch 11 to the original exposure position 44 is longer than the length of the original transport path of the photosensitive drum 20. From the transfer position 20b to the transfer position 20b. Thus, an image corresponding to the rear end of the document 9 can be formed on the rear end of the roll sheet 4 obtained by cutting at the above timing.

The second document end detection switch 16
Switches from on to off when the document 9 is conveyed in the reverse direction R2, thereby detecting the rear end of the document 9 conveyed in the reverse direction R2. When the leading edge detection switch 16 is turned off, the driving of the transport rollers 12, 14, 15 is stopped. At this time, the leading end of the document 9 is held between the transport rollers 12, and is ready for the next copy operation. Reference numeral 8 denotes a reversing member for reversing the direction of the original to prevent the original 9 from dropping behind the copying machine body 1.

In connection with the transparent plate 13, a light source 17 for illuminating the original surface of the original 9 is fixedly arranged. The light from the light source 17 is applied to the surface of the document via the transparent plate 13. Then, the reflected light from the surface of the document 9 is guided by the selfoc lens 18 to the surface of the photosensitive drum 20 provided substantially at the center of the copying machine main body 1. The photosensitive drum 2 before being exposed by the light from the selfoc lens 18
0 is uniformly charged by the charging corona discharger 21. Therefore, an electrostatic latent image corresponding to the original image is formed on the surface of the photosensitive drum 20 after the exposure. This electrostatic latent image is visualized into a toner image by the developing device 22. This toner image is guided to the vicinity of the transfer corona discharger 24 by rotating the photosensitive drum 20 in the direction of the arrow 23.

On the other hand, the transport routes D1, D2, D3 or D
The sheet 4 guided to the photoconductor drum 20 from the photoconductor 4 is guided to the vicinity of the transfer corona discharger 24 while being in contact with the surface of the photoconductor drum 20. The toner image on the surface of the drum 20 is transferred to the sheet 4. The sheet 4 to which the toner image has been transferred is
The photosensitive drum 20 is separated from the surface of the photosensitive drum 20 by corona discharge in the separating corona discharger 25, and further guided to the fixing device 35 through the conveyance path 34. In the fixing device 35, the toner is fixed on the surface of the sheet 4 by heating and pressing the sheet 4 between the heat roller 37 and the pressure roller 38. The sheet 4 on which the toner has been fixed is discharged from the discharge roller 36 to the outside of the copying machine 1 via the discharge detection switch 55, and is stored in the pocket 92 via the guide member 91 as described above. On the other hand, the toner remaining on the surface of the photosensitive drum 20 after the transfer of the toner image is removed by the cleaning device 26, and the preparation for forming the next electrostatic latent image is made.

A guide auxiliary plate 94 is arranged above the guide member 91. This guide auxiliary plate 94
Is a stay 9 attached to the front surface 1a of the copying machine body 1.
5, the guide attitude of guiding the sheet hanging down and ejected forward of the guide member 91 to the pocket 92 together with the guide member 91 by the rotation (indicated by a dashed line in FIG. 1). And a storage posture (shown by a solid line in FIG. 1) held by the stay 95.

The photosensitive drum 20, the developing device 22, the transfer corona discharger 24 and the like constitute an image forming means. In this embodiment, a main motor MM for driving the image forming unit, a paper feeding motor DM for driving a roller group for feeding the sheets 4A to 4D, and a heat roller of the fixing device 35 37 and pressure roller 38
Fixing motor FM for driving the like and the like, the document conveying section 10
And a document feed motor OM for driving the document feeder.

FIG. 4 is a block diagram showing a configuration of a control circuit which is a feature of the copying machine according to the present embodiment, and FIG. 5 is an operation timing chart of the control circuit. First, referring to FIGS. 1 and 4, one of the features of this copying machine is as follows.
The cut sheet conveyed along the bypass conveyance path D4 is improved so as not to be obliquely shifted from the conveyance direction in the bypass conveyance path D4, that is, not to be skewed. The skew prevention of the cut sheet is realized by slightly lowering the rotation peripheral speed of the registration roller 39 with respect to the rotation peripheral speed of the transport roller 33, as described later.

Another feature of the present embodiment is that when a cut sheet is conveyed along the bypass conveyance path D4 and the rear end of the cut sheet is separated from the registration roller 39, the tension applied to the cut sheet suddenly increases. That is, the load of the transport roller 33 is changed and the cut sheet is not vibrated with the load, thereby preventing the transferred toner image from being shifted. The processing for preventing the image shift from occurring on the cut sheet as described above is also performed by the registration roller 3.
9 by controlling the peripheral speed of rotation.

Referring to FIG. 4 more specifically,
A control circuit 220 for controlling the main motor MM and the paper feeding motor DM is provided. This control circuit 2
Reference numeral 20 may be a dedicated control circuit or a control circuit for controlling the operation of the entire copying machine, for example, a part of a CPU or the like. The control circuit 220 is supplied with signals from the fifth tip detection switch 75, the sixth tip detection switch 76, and the second tip detection switch 72. The control circuit 220 controls the rotation of the main motor MM and the paper feed motor DM based on these signals, and also controls the clutches 221, 222, and 223 to control the conveyance roller 33, the registration roller 39, and the separation roller 32. Control rotation / stop.

Next, the rotation of the photosensitive drum 20, the transport roller 33, the registration roller 39, and the separation roller 32 controlled by the control circuit 220 will be described with reference to the timing chart shown in FIG. First, the main motor MM is driven, and the rotation of the photosensitive drum 20 is started. In this state, a cut sheet is inserted from the manual paper feed unit 30. Then, the fifth leading edge detection switch 75 is first turned on by the leading edge of the cut sheet.

The control circuit 220 rotates the sheet feeding motor DM and turns on the clutch 223 in response to the ON signal of the fifth leading edge detection switch 75, and
Rotate 2. As a result, the cut sheet inserted from the manual paper feed unit 30 is taken in, and
It is sent to 9. In this case, when there are a plurality of cut sheets inserted from the manual paper feed unit 30, one cut sheet is taken in by the separation roller 32.

When the cut sheet is taken in by the separation roller 32, the leading end of the taken cut sheet turns on the sixth leading end detection switch 76. The ON signal of the sixth tip detection switch 76 is given to the control circuit 220.
The control circuit 220 turns off the clutch 223 and stops the rotation of the separation roller 32 a predetermined time after the ON signal is given. The reason why the clutch 223 is turned on a predetermined time after the ON signal of the sixth leading edge detection switch 76 is given is to ensure that the leading edge of the cut sheet taken in abuts against the registration roller 39 and stops. is there. That is, when the cut sheet inserted from the manual sheet feeding unit 30 is slightly distorted with respect to the bypass conveyance path D <b> 4, only a part of the leading end of the cut sheet first strikes the registration roller 39. In this state, when the sheet is further fed by the separation roller 32, the cut sheet that has been distorted is corrected so as to be straight to the bypass conveyance path D4. Then, the entire leading end of the cut sheet comes into contact with the registration roller 39. That is, the leading end of the cut sheet is aligned with a line extending in a direction orthogonal to the transport direction.

Thereafter, the clutch 222 is turned on at a predetermined timing, and the registration roller 39 is rotated by the paper feeding motor DM. By the rotation of the registration rollers 39, the cut sheet is conveyed along the bypass conveyance path D4, and the leading end of the cut sheet reaches the conveyance roller 33. Since the second leading edge detection switch 72 is provided immediately before the transport roller 33, when the leading edge of the cut sheet reaches the transport roller 33, the second leading edge detection switch 72 is provided.
Turns on.

When an ON signal of the second leading end detection switch 72 is given, the control circuit 220 turns off the clutch 222 and stops the registration roller 39. In this state,
The conveyance of the document conveyed by the document conveyance unit 10 is synchronized with the conveyance of the document, and the clutch 221 and the clutch 222 are turned on at a predetermined timing corresponding to the conveyance of the document. Thereby, the transport roller 33 and the registration roller 3
9 is rotated, and the cut sheet is conveyed.

In this case, the peripheral speed of the transport roller 33 and the peripheral speed of the registration roller 39 are different from each other. Specifically, the rotation peripheral speed of the registration roller 39 is set to be lower by about 1 to 2% than the rotation peripheral speed of the transport roller 33. As a result, the cut sheet conveyed by the conveyance roller and the registration roller 39 is relatively quickly fed by the conveyance roller 33,
Is sent relatively late. As a result, a constant tension is always applied to the cut sheet traveling from the registration roller 39 to the transport roller 33. When such tension is applied to the cut sheet conveyed along the conveyance path, the cut sheet conveyed is shifted obliquely with respect to the conveyance path between the registration roller 39 and the conveyance roller 33, that is, the cut sheet Can be prevented from skewing.

As described above, the copying machine according to the present embodiment is a copying machine capable of copying a large-size original such as an A0 plate. For example, when copying an A0 original, a copy sheet inserted from the manual paper feed unit 30 is also used.
It is a large size called A0 version. Even when the leading end of the large-sized copy sheet is being conveyed from the transport roller 33 to the photosensitive drum 20, the trailing end of the large-sized copy sheet is still hanging from the entrance of the manual paper feed unit 30. Thereafter, as the conveyance of the copy sheet proceeds, the rear end of the copy sheet eventually passes through the fifth leading edge detection switch 75.
When the trailing edge of the copy sheet passes through the fifth leading edge detection switch 75, the fifth leading edge detection switch 75 is turned off.

The control circuit 220 increases the rotation speed of the paper feed motor DM in response to the off signal of the fifth leading edge detection switch 75. By increasing the rotation speed of the paper feeding motor DM, the rotation peripheral speed of the registration roller 39 is increased. As a specific example, the rotation peripheral speed of the registration roller 39 is increased by about 5 to 7%. Registration roller 39
Is increased not by switching the clutch or the like but by increasing the rotation speed of the paper feed motor DM.
The peripheral speed is smoothly increased. Therefore, the transport rollers 33
The cut sheet conveyed by the registration roller 39 is not subjected to any impact or the like, and the registration roller 3
The tension applied to the cut sheet sent to the conveying roller 33 from 9 is smoothly removed.

Thereafter, the trailing edge of the cut sheet passes through the sixth leading edge detection switch 76 and the sixth leading edge detection switch 7
6 is turned off, and then the rear end of the cut sheet is separated from the registration roller 39. When the rear end of the cut sheet separates from the registration roller 39, the tension applied to the cut sheet between the registration roller 39 and the conveyance roller 33 is removed as described above. The moment you leave the registration roller 39,
There is no load fluctuation of the transport roller 33, and no vibration or the like is applied to the cut sheet.

The clutch 222 is turned off and stopped after a predetermined time, for example, about one second, after the sixth tip detection switch 76 is turned off. afterwards,
The rear end of the conveyed cut sheet passes through the second leading edge detection switch 72, and the second leading edge detection switch 72 is turned off. Then, the rear end of the cut sheet is sent from the conveying roller 33 to the photosensitive drum 20. After the rear end of the cut sheet leaves the transport roller 33, that is, a predetermined time after the second detection switch 72 is turned off, the clutch 221 is turned off and the transport roller 33 is stopped.

In this embodiment, as described above, the leading ends of cut sheets inserted into the bypass conveyance path D4 are first aligned on a line orthogonal to the conveyance direction by the registration rollers 39 provided on the bypass conveyance path D4. To be.
Then, conveyance of the cut sheet is started in that state, and a predetermined tension is constantly applied to the cut sheet conveyed from the registration roller 39 to the conveyance roller 33. Thus, the cut sheet being conveyed does not shift obliquely with respect to the conveyance path.

Further, tension is always applied to the cut sheet conveyed from the registration roller 39 to the conveyance roller 33. When the rear end of the cut sheet conveyed as it is is separated from the registration roller 39, the cut sheet is cut from the registration roller 39. At the moment when the trailing edge of the sheet is released, the tension applied to the cut sheet suddenly disappears.
There is a possibility that a load fluctuation occurs in No. 3 and a vibration or the like occurs in the cut sheet.

Therefore, in this embodiment, when the rear end of the cut sheet conveyed is near the registration roller 39, the peripheral speed of the registration roller 39 is increased, and the cut sheet is conveyed from the registration roller 39 to the conveyance roller 33. The tension applied to the cut sheet was removed smoothly. This can prevent skew and image misalignment of a large cut sheet conveyed on the bypass conveyance path D4.

Although the copying machine according to the present embodiment employs a configuration in which a roll sheet is normally used as a copy sheet and a cut sheet can be inserted as a copy sheet from the manual feed unit 30 by manual feeding, Accordingly, the configuration of the present invention can be applied to a copying machine in which a cut sheet is always used as a copy sheet.

[0043]

According to the present invention, when forming an image on a large-sized copy sheet, particularly a long copy sheet, it is possible to prevent the copy sheet from being skewed at the time of conveyance and to cause distortion in the formed image. An improved copier can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically illustrating an internal configuration of a copying machine according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an external configuration of a copying machine according to an embodiment of the present invention.

FIG. 3 is a perspective view showing an appearance of the copying machine according to the embodiment of the present invention at the time of copying.

FIG. 4 is a block diagram illustrating a configuration of a control circuit of a transport path for transporting cut sheets of the copying machine according to one embodiment of the present invention.

FIG. 5 is a timing chart showing the operation timing of the transport control of the control circuit in FIG. 4;

[Explanation of symbols]

 REFERENCE SIGNS LIST 20 photoconductor drum 22 developing device 24 transfer corona discharger 30 manual feed unit 32 separation roller 33 transport roller 39 registration roller 72 second tip detection switch 75 fifth tip detection switch 76 sixth tip detection switch 220 control Circuit 221, 222, 223 Clutch D4 Bypass conveyance path MM Main motor DM Feed motor

Continuation of the front page (56) References JP-A-62-130944 (JP, A) JP-A-4-157481 (JP, A) JP-A-63-258357 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) B65H 9/00-9/20 B65H 5/06

Claims (2)

(57) [Claims] An image forming section including a photoreceptor, forming an image to be copied on the photoreceptor by electrophotography, and transferring the formed image to a given copy sheet, and transferring the copy sheet to the image forming section A transport path for guiding, a transport roller provided at a position near the image forming unit in the transport path, for supplying a copy sheet to the image forming unit at a predetermined transport speed, and a transport of the copy sheet in the transport path. A registration roller provided upstream of the position of the conveyance roller when viewed in the direction, and a sheet provided upstream of the position of the registration roller in the conveyance direction of the copy sheet in the conveyance path. An edge detection unit, wherein when the image forming unit starts transferring the image to the leading end of the copy sheet, the trailing end of the copy sheet is located on the upstream side of the sheet edge detection unit in the transport direction. Sheet A copying machine that performs copying on the copy sheet between the conveyance roller and the registration roller when the sheet edge detection means does not detect the end of the copy sheet being conveyed along the conveyance path. as copy sheet in <br/> pressurized forte conveying a predetermined tension is not displaced obliquely, the registration roller is rotated at a predetermined speed slower first peripheral speed than the peripheral speed of the transport rollers, the sheet In response to the edge detecting means detecting the edge of the copy sheet being conveyed along the conveyance path, the tension applied to the copy sheet between the conveyance roller and the registration roller is smoothly reduced.
A copying machine comprising: a registration drive control unit configured to increase the registration roller from a first peripheral speed to a second peripheral speed that is higher than the peripheral speed of the transport roller by a predetermined speed. 2. A copying machine that uses a roll sheet drawn from a roll body formed by winding a long sheet or a cut sheet cut to a predetermined size as a copy sheet, including a photoconductor. An image forming unit that forms an image to be copied on a photoreceptor by electrophotography and transfers the formed image to a given copy sheet; a roll sheet transport path for guiding the roll sheet to the image forming unit; A conveying roller provided at a position near the image forming unit in the vicinity of the image forming unit, for feeding a sheet to the image forming unit at a predetermined conveying speed, and for guiding a cut sheet cut to a predetermined size. The leading end of the path is joined to the roll sheet transport path so as to guide the cut sheet to the transport rollers, and the trailing end of the path is cut. A cut sheet transport path having a sheet insertion opening; a registration roller provided in the cut sheet transport path; and a cut roller provided in the cut sheet transport path at a position upstream of the registration roller arrangement position when viewed in the cut sheet transport direction. In the state where the sheet edge detecting means is not detecting the edge of the cut sheet being conveyed in the cut sheet conveying path, the sheet edge detecting means always applies a predetermined amount to the cut sheet between the conveying roller and the registration roller. I the tension copy sheet being pressurized forte conveyed not displaced obliquely <br/> urchin, the registration rollers, is rotated at a predetermined speed slower first peripheral speed than the peripheral speed of the transport rollers, the sheet end portion In response to the detection unit detecting the end of the cut sheet being conveyed along the cut sheet conveyance path, the detection means is added to the cut sheet between the conveyance roller and the registration roller. And as tension is eliminated smoothly, the registration roller, the first
A registration drive control means for increasing the peripheral speed from a peripheral speed to a second peripheral speed higher than the peripheral speed of the transport roller by a predetermined speed.