JPH08239153A - Electrostatic copying machine - Google Patents

Abstract

PURPOSE: To restrain copying paper from curling when introduced into a feed reversing passage by providing a feed reversing means with the feed reversing passage having a curved part, and providing a cooling means for cooling the outside surface of the curved part of the copying paper introduced. CONSTITUTION: Copying paper P with an image thermally fixed thereon by a pair of thermal fixing rollers is introduced into a feed reversing passage 129 as indicated by the two-dot chain line, but since the feed reversing part 129 is curved the paper tends to curl along this curved part. However, an outside guide plate 130 forming the outside of the curved part of the feed reversing passage 129 is provided with a plurality of openings 132, so that cold air works through the openings 132 on the outside surface of the curved part of the copying paper P introduced into the feed reversing passage 129. Therefore, the copying paper P introduced into the feed reversing passage 129 is cooled at the outside surface of its curved part, shrinks in the opposite direction to the curling direction, and is kept from curling.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic copying machine, and more particularly to an electrostatic copying machine capable of forming an image on both sides of a copying paper as required.

[0002]

2. Description of the Related Art From the standpoint of saving copy paper and reducing the number of documents to be stored, there is a large demand for forming images on both sides of the copy paper. An electrostatic copying machine capable of forming an image on both sides of the sheet has been proposed and put into practical use. In such an electrostatic copying machine, generally, a copy paper conveying means for defining a copy paper conveying path, a copy paper supplying means for supplying a sheet copy paper to the copy paper conveying path, and the copy paper conveying path. A copy paper discharging means which is disposed on the downstream side of the copy paper and defines a copy paper discharging path; and a copy paper returning means which defines a copy paper returning path connected to a connecting portion between the copy paper conveying path and the copy paper discharging path,
A transport switching mechanism for selectively guiding the copy sheet transported by the copy sheet transporting means to the copy sheet discharging path or the copy sheet returning path, and before and after the copy sheet when guiding the copy sheet to the copy sheet returning path. And a reversal means for reversing the direction and a reversal means for receiving the copy paper returned through the copy paper return path and re-supplying the accepted copy paper to the copy paper transport path. ing.

In such an electrostatic copying machine, an image is formed on one side of the copy paper while the copy paper supplied from the copy paper supply means to the copy paper carrying path is carried through the copy paper carrying path. To be done. When it is desired to form an image on only one side of the copy paper, the copy paper on which the image is formed on one side is guided to the copy paper discharge path by the transport switching mechanism and passes through the copy paper discharge path. It is discharged outside the copier. On the other hand, when it is desired to form an image on both sides of the copy sheet, the copy sheet having the image formed on one side is guided to the feed reversing means by the transport switching mechanism, and the feed reversing means of the feed reversing means. By the action, the front-back direction of the copy paper is reversed, the copy paper is introduced from the rear end into the copy paper return path, and is received by the copy paper retransmitting means through the copy paper return path. After that, the copy paper is re-supplied from the copy paper retransmitting means to the copy paper transport path, and an image is formed on the other surface of the copy paper while being re-transported through the copy paper transport path. In this way, the copy paper with images formed on both sides is
It is guided to the copy paper discharge path by the transport switching mechanism and is discharged to the outside of the copying machine through the copy paper discharge path.

[0004]

The feeding reversing means is
It is necessary to temporarily store the copy paper in order to have the function of reversing the front-back direction of the copy paper. Therefore, the feed reversal path having a length corresponding to the length of the maximum copy paper used in the transport direction is provided. There is. It is desirable that the feed reversal path be as linear as possible, but the curved portion must be provided because of the arrangement space. Thus, the copy paper introduced into the feed reversal path is immediately after the image is formed on one side and is heated in the fixing step, so if it is introduced into the feed reversal path having the curved portion, A so-called paper curl that bends along the bending portion occurs. If the degree of this paper curl is large, the conveyance failure of the copy paper occurs, which causes paper jam.

The present invention has been made in view of the above points, and its main technical problem is to suppress the occurrence of so-called paper curl which occurs when a copy sheet is introduced into a feed reversal path having a curved portion. Another object of the present invention is to provide an electrostatic copying machine capable of performing the above.

[0006]

In order to achieve the above main technical problem, according to the present application, a copy sheet conveying means for defining a copy sheet conveying path, and a sheet-like copy sheet in the copy sheet conveying path. For supplying the copy paper, a copy paper discharging means arranged downstream of the copy paper transport path for defining a copy paper discharge path, and a connection between the copy paper transport path and the copy paper discharge path. Copy paper returning means for defining a copy paper returning path connected to the copying machine, and a conveyance switching mechanism for selectively guiding the copy paper conveyed by the copy paper conveying means to the copy paper discharging path or the copy paper returning path. A feed reversing means for reversing the longitudinal direction of the copy sheet when guiding the copy sheet to the copy sheet returning path; and a copy sheet that has received and received the copy sheet returned through the copy sheet returning path. For re-supplying to the copy paper transport path In the electrostatic copying machine provided with the copying paper retransmitting means, the feeding reversing means has a feeding reversing path having a curved portion for introducing the copying paper, and the copying paper introduced into the feeding reversing path. An electrostatic copying machine is provided, which is provided with a cooling means for cooling the outer side surface of the curved portion.

Further, according to the present application, the feed reversal path having the curved portion is defined by the outer guide plate forming the outer side of the curved portion and the inner guide plate forming the inner side of the curved portion, There is provided an electrostatic copying machine in which the cooling means comprises an opening formed in an outer guide plate which defines a feed reversal path.

[0008]

In the electrostatic copying machine according to the present invention, when an image is formed on both sides of a copy sheet, the copy sheet having the image formed on one side is introduced into the feed reversing path in the feed reversing means. At this time, since an opening is provided in the outer guide plate that forms the outside of the curved portion in the feed reversal path, cold air acts through the opening on the outer surface of the curved portion of the copy paper introduced into the feed reversal path. To do. Therefore, in the copy paper introduced into the feed reversal path, the outer surface of the curved portion is cooled,
The contraction that acts in the direction opposite to the curl direction along the curved portion occurs, and the occurrence of paper curl is suppressed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A more detailed description will be given below with reference to the accompanying drawings showing a preferred embodiment of an electrostatic copying machine constructed according to the present invention. FIG. 1 schematically illustrates the main components in an embodiment of an electrostatic copying machine constructed according to the present invention. The electrostatic copying machine shown in FIG. 1 includes a housing 2 having a substantially rectangular parallelepiped shape. On the upper surface of the housing 2, a stationary transparent plate 4 on which a document (not shown) to be copied is placed, and an openable and closable document holder for covering the transparent plate 4 and the document placed on the transparent plate 4. The member 6 is provided. A rotary drum 8 having an electrostatic photosensitive member on its peripheral surface is rotatably mounted in a substantially central portion of the housing 2. A charging area 12, an exposure area 14, a developing area 16, a transfer area 18, and a cleaning area 20 are sequentially arranged around the rotary drum 8 which is rotationally driven in the direction indicated by the arrow 10, when viewed in the direction indicated by the arrow 10. It is set up. The charging area 12 is provided with a charging corona discharger 22, the developing area 16 is provided with a developing device 24, and the transfer area 18 is provided with a transfer corona discharger 26 and a peeling corona discharger 28. And the cleaning area 20 has a residual toner removing blade 32.
Is provided.

Above the rotary drum 8, the whole number 34
The optical system indicated by is provided. The optical system 34 includes a movable original illumination lamp 36, a first movable reflecting mirror 38, a second movable reflecting mirror 40, a third movable reflecting mirror 42, a stationary lens assembly 44 and a stationary reflecting mirror 46. . At the time of scanning exposure, the movable original illumination lamp 36 and the first movable reflecting mirror 38 move the required speed V from the scanning exposure start position shown in FIG. 1 to the right substantially horizontally to the maximum scanning exposure end position.
The second movable reflecting mirror 40 and the third movable reflecting mirror 42 are moved substantially horizontally to the right from the scanning exposure start position shown in FIG. 1 to, for example, the maximum scanning exposure end position by half the required speed. It can be moved at the speed of V / 2. At this time, the manuscript placed on the transparent plate 4 is illuminated by the movable manuscript illumination lamp 36, and the reflected light from the manuscript is reflected in FIG.
As indicated by the alternate long and short dash line in FIG. 1, the light is sequentially reflected by the first, second and third movable reflecting mirrors 38, 40 and 42 to reach the lens assembly 44, and then is reflected by the stationary reflecting mirror 46 to expose the exposure area. At 14, the image is projected onto the photoconductor of the rotary drum 8. When the scanning exposure is completed, the movable original illumination lamp 36 and the first, second and third reflecting mirrors 38, 4 are provided.
0 and 42 are returned to the scanning exposure start position.

At one end portion of the housing 2, that is, at the right end portion in FIG. The illustrated copy sheet feeding means 48 includes a lower cassette receiving portion 50a, an intermediate cassette receiving portion 50b and an upper cassette receiving portion 50c. Lower cassette receiving part 5
0a, the intermediate cassette receiving portion 50b, and the upper cassette receiving portion 50c are selectively and removably attached to any one of several types of copy paper cassettes 52 containing sheet copy papers having different sizes. It Lower cassette receiving part 5
0a, the intermediate cassette receiving portion 50b, and the upper cassette receiving portion 50c, respectively, a delivery roller 54 for delivering one copy sheet from the copy sheet cassette 52 mounted therein.
a, 54b and 54c are provided. The copy sheet sent from the copy sheet cassette 52 mounted on the lower cassette receiving portion 50a is introduced into the copy sheet conveying path indicated by numeral 58 through the copy sheet feeding path 56a. The copy paper sent from the copy paper cassette 52 mounted on the intermediate cassette receiving portion 50b is transferred to the copy paper feeding paths 56b and 56.
It is introduced into the copy paper conveyance path 58 through a. The copy paper delivered from the copy paper cassette 52 mounted in the upper cassette receiving portion 50c is introduced into the copy paper transport path 58 through the copy paper feed paths 56c, 56b and 56a. The copy paper feed path 56a is defined by guide plates 62 and 64, the copy paper feed path 56b is defined by guide plates 66, 68 and 70, and a pair of feed rollers 72, and the copy paper feed path 56c is a guide plate. 68, 70, 74 and 76 and the feed roller pair 78.
The illustrated copy paper supply means 48 further includes a paper feed table mechanism 80. The paper feed table mechanism 80 includes a vertically movable table (not shown), and a delivery roller 82 is arranged above the table. Table mechanism 80
The copy paper sent from the copy paper transport path 58d passes through the copy paper feed path 56d and a copy paper re-supply path described later.
Will be introduced to. The copy sheet feeding path 56d is defined by the guide plates 84 and 86 and the feeding roller pair 88.

The copy paper transport path 58 extends from the upstream end 90 to the downstream end 92 substantially horizontally from right to left in FIG. The copy sheet conveying path 58 includes a downstream portion of the guide plate 64 and a downstream portion of the guide plate 94, a pair of conveying rollers 96,
Guide plate pair 98, conveyance roller pair 100, guide plate 102, the transfer area 18 (that is, between the rotary drum 8 and the transfer corona discharger 26 and the peeling corona discharger 28), the transfer belt mechanism 104, the guide plate 106. , Heating fixing roller pair 108
And a guide plate 110, which constitute a copy sheet conveying means.

A transport switching means 114 is disposed adjacent to the downstream end 92 of the copy paper transport path 58. The illustrated conveyance switching means 114 is a conveyance roller mechanism 118 including three rollers arranged in the vertical direction, that is, an upper roller 115, an intermediate roller 116 and a lower roller 117, and a pair of guides defining a conveyance switching path 121. It includes members, a lower guide member 119 and an upper guide member 120. The upper roller 115, the intermediate roller 116, and the lower roller 117 are rotated in the directions indicated by the arrows, respectively, and the lower guide member 119 and the upper guide member 120 are selectively moved to the lowered position shown by the solid line and the raised position shown by the chain double-dashed line. Positioned. A copy paper discharge path 122 is arranged downstream of the transport switching means 114. The copy paper discharge path 122 is defined by the guide plate 123 and discharge rollers 124 and 125, and these constitute copy paper discharge means. The tray 126 is detachably attached to the other end of the housing 2, that is, the left end in FIG.

In connection with the transfer switching means 114,
A feed reversing means 127 and a copy paper returning means 128 are provided. The illustrated feeding reversing means 127 includes a feeding reversing path 129 having a curved portion that guides and holds a copy sheet. The feeding reversing path 129 includes an outer guide plate 130 that forms the outside of the curving portion. It is defined by an inner guide plate 131 that forms the inside of the curved portion. Feeding reversal route 1
The outer guide plate 130, which constitutes 29, has a plurality of openings 132, 132, ... As shown in FIGS.
.. are formed at intervals in the width direction. The feed reversing means 127 also includes a reverse feeding roller 133.
The reverse feeding roller 133 is selectively positioned at the non-acting position shown by the solid line and the working position shown by the chain double-dashed line. When the reverse feeding roller 133 is positioned at the operating position indicated by the chain double-dashed line, it acts on the conveying roller 135 attached to the shaft 134 on which the one discharging roller 125 of the discharging rollers is mounted. The reverse feed roller 133 is operated from the non-acting position to the working position by the reverse feed roller operating means 136 (see FIG. 2). The reverse feeding roller operating means 136 includes a rotating shaft 138, an arm 139 for connecting the shaft 137 rotatably mounted with the reverse feeding roller 133 to the rotating shaft 138,
It comprises an operating lever 140 connected to the rotating shaft 138 and a solenoid 141 for operating the operating lever 140. The rotating shaft 138 is biased by a biasing means (not shown) so as to rotate counterclockwise in FIG. 2. Therefore, when the solenoid 141 is de-energized, the biasing means (not shown) is biased. The rotating shaft 138 is rotated counterclockwise by the urging force, whereby the reverse feeding roller 133 is positioned at the non-acting position shown by the solid line via the arm 139 and the shaft 137. On the other hand, when the solenoid 141 is biased, the rotary shaft 138 is rotated clockwise against the biasing force of the biasing means (not shown) via the actuating lever 140, whereby the arm 139 and the shaft 137 are moved. The reverse feeding roller 133 is positioned at the operating position indicated by the chain double-dashed line.

The copy paper returning means 128 is a returning means 15.
0 and the return control means 152, and defines a copy paper return path 154 extending from the upstream end adjacent to the upstream end of the transport switching mechanism 114 to a slight downward inclination from left to right in FIG. The illustrated returning means 150 includes a guide plate pair 156, a conveying roller pair 158, a guide plate pair 160, a conveying roller pair 162,
Guide plate pair 164, conveyance roller pair 166, and guide plate pair 1
68, which defines the upstream side of the copy sheet return path 154, and the return control mechanism 152 shown in the figure
70, swinging member 172, guide plate 174, pair of transport rollers 1
76, a swinging member 178, a guide plate 180, and a pair of conveying rollers 182, and defines a downstream side portion of the copy paper returning path 154. The swing members 172 and 178 are swingable between a position shown by a solid line in FIG. 1 and a position shown by a chain double-dashed line in FIG. As will be easily understood by referring to FIG. 1, when the lower guide member 119 and the upper guide member 120 of the transport switching mechanism 114 are positioned at the lower position shown by the solid line, the copy paper transport path 58 and the copy paper discharge are performed. The path 122 and the path 122 communicate with each other via the transfer switching path 121 in the transfer switching mechanism 114. On the other hand, when the lower guide member 119 and the upper guide member 120 are positioned at the raised position shown by the chain double-dashed line, the copy paper transport path 58 and the feed reversal path 129 are routed through the transport switching path 121 in the transport switching mechanism 114. The feed reversal path 129 and the copy paper return path 154 are communicated with each other via the transport switching path 121 in the transport switching mechanism 114.

In the illustrated electrostatic copying machine, a copy paper retransmitting unit indicated by reference numeral 190 is disposed below the copy paper returning path 154. This copy paper retransmitting means 1
90 has a pedestal 192. In the illustrated embodiment, the front part of the pedestal 192 is defined by the upper surface of the receiving block 194, and the rear part thereof is provided on the upper surface of the receiving block 194 at intervals in the width direction (direction perpendicular to the paper surface in FIG. 1). Is defined by the upper edge of the received ridge 196. The rear part of the pedestal 192 extends slightly downward in the copy sheet feeding direction, and the front part extends substantially horizontally. Stop means 198 is arranged at the front end of the pedestal 192, that is, at the right end in FIG. The stopping means 198 is selectively positioned at either the operating position shown by the solid line or the non-operating position shown by the chain double-dashed line. A feeding roller 200 is provided above the front end of the pedestal 192. The feeding roller 200 is mounted so as to be able to freely move upward from a position in contact with the upper surface of the pedestal 192 (position indicated by a chain double-dashed line in FIG. 1) to a predetermined position (position indicated by a solid line in FIG. 1). And is normally forced downward by the biasing effect of its own weight (optional spring means if necessary). Further, there is provided a copy paper re-supply path indicated by reference numeral 202, which extends from the front end of the copy paper retransmitting means 190 to the upstream end 90 of the copy paper transport path 58. The copy paper re-supplying means that defines the copy paper re-supply path 202 includes a separation roller pair 204, a guide plate pair 206, a re-supply roller pair 208, and a guide plate pair 21.
0, resupply roller pair 212, guide plates 84, 86, 21
4, a re-supply roller pair 216 and guide plates 94, 218.

The electrostatic copying machine according to the illustrated embodiment is constructed as described above, and its operation will be described below.
The rotary drum 8 is rotated in the direction indicated by the arrow 10.
In the charging area 12, the surface of the photoconductor on the rotary drum 8 is charged to a specific polarity by the charging corona discharger 26, and in the exposure area 14, the image of the original placed on the transparent plate 4 is converted into the optical system. Scanning exposure on the photoconductor by 34,
Thus, an electrostatic latent image is formed on the photoconductor. Development area 16
In the above, the developing device 24 applies toner to the electrostatic latent image on the photoconductor to develop the electrostatic latent image into a toner image.
In the transfer area 18, copy paper conveyed through the transfer area 18 (conveyance of copy paper will be described in detail later) is brought into contact with the surface of the photoconductor, and the transfer corona discharger 2
By the action of 6, the toner image on the photoconductor is transferred onto the copy paper. Next, the copy paper is peeled from the photoconductor by the action of the peeling corona discharger 28. The peeled copy paper is conveyed to the heat fixing roller pair 108, and the toner image is fixed on the copy paper when passing through the heat fixing roller pair 108. On the other hand, in the cleaning area 20, the residual toner is removed from the surface of the photoconductor by the action of the residual toner blade 32.

Next, the conveyance of copy paper will be described.
It is as follows. First, a case of forming an image on only one side of copy paper will be described. In this case, the lower guide member 118 and the upper guide member 12 of the transport switching mechanism 114 are used.
0 is located in the lowered position shown by the solid line. It is introduced into the copy paper transport path 58 from the copy paper cassette 52 mounted on the lower cassette receiving portion 50a, the intermediate cassette receiving portion 50b or the upper cassette receiving portion 50c, or the table (not shown) of the paper feeding table mechanism 80. The copy paper is conveyed through the copy paper conveyance path 58. During this time, the transfer area 18
At, the toner image is transferred onto one side (that is, the upper surface) of the copy paper, and the toner image is fixed on the one side of the copy paper by the action of the heating and fixing roller pair 108, thus forming an image on the one side of the copy paper. Next, the copy paper is transferred to the upper roller 115 and the intermediate roller 11 of the transport switching mechanism 114.
6 from the copy paper transport path 58 to the transport switching path 12
1 and is discharged to the tray 126 through the transport switching path 121 and the copy paper discharge path 122. In this way, a copy having an image formed on one side thereof is obtained.

When images are formed on both sides of copy paper,
First, the lower guide member 119 and the upper guide member 120 of the transport switching mechanism 114 are positioned at the raised position shown by the chain double-dashed line. Then, when the copying process is started, the copy paper cassette 52 mounted on the lower cassette receiving portion 50a, the intermediate cassette receiving portion 50b or the upper cassette receiving portion 50c, or the table (not shown) of the paper feeding table mechanism 80. The copy paper introduced from the copy paper conveyance path 58 is conveyed through the copy paper conveyance path 58. During this time, the transfer area 18
At, the toner image is transferred onto one side (that is, the upper surface) of the copy paper, and the toner image is fixed on the one side of the copy paper by the action of the heating and fixing roller pair 108, thus forming an image on the one side of the copy paper. The copy sheet from the copy sheet transport path 58 is introduced into the transport switching path 121 through the upper roller 115 and the intermediate roller 116 of the transport switching mechanism 114, and is fed through the transport switching path 121 to the feed reversing mechanism 12.
7 through the feed reversal path 129. At this time, the lower surface of the copy paper comes into contact with one of the discharge rollers 125 located above the discharge roller that is being driven to rotate in a predetermined direction. Glipping is created and, therefore, the copy paper can advance in a given direction despite the rotational drive of such rollers. The trailing edge of the copy paper is the copy paper transport path 58.
When it passes through the downstream end of the feed roller (specifically, when it passes through the nip portion of the upper roller 115 and the intermediate roller 116), the solenoid 141 is energized, and the reverse feed roller 133 provided at the upstream end of the feed reversal path 129. Is positioned at the operating position indicated by the chain double-dashed line, whereby the copy paper is pressed against the transport roller 135 mounted on the shaft 134 on which the discharge roller 125 is mounted. As a result, due to the action of the transport roller 135 that is being driven to rotate in a predetermined direction, the copy paper advances in the reverse direction through the transport switching path 121, and passes between the intermediate roller 116 and the lower roller 117. It is introduced into the return path 154 and proceeds through the copy paper return path 154. In this way, the solenoid 141 is deenergized at an appropriate time after the copy paper is introduced into the copy paper return path 140, and the feed reversing mechanism 127 is turned on.
The reverse feeding roller 133 at is returned to the non-acting position shown by the solid line. As described above, the copy sheet P heat-fixed by the heat-fixing roller pair 108 is introduced into the feed reversal path 129 as shown by the chain double-dashed line in FIG. 1, but the feed reversal path 129 is curved. Due to this, there is a tendency to curl along the bend. However, in the illustrated embodiment, a plurality of openings 132, 132, ... Are formed in the outer guide plate 130 that forms the outer side of the curved portion in the feed reversal path 129.
Are provided, the cool air acts on the outer side surface of the curved portion of the copy paper P introduced into the feed reversal path 129 through the opening. Therefore, since the outer side surface of the curved portion of the copy paper P introduced into the feed reversal path 129 is cooled, contraction that acts in the direction opposite to the curl direction occurs, and the occurrence of paper curl is suppressed. It

As described above, the copy paper return path 154
Copy paper that is made to progress through the copy paper retransmitting means 1
It is guided to the pedestal 192 of 90, and advances rightward on the pedestal 192 in FIG. In the illustrated embodiment, when a relatively long copy sheet is returned through the copy sheet return path 154, the swinging member 171 is switched from the position shown by the solid line in FIG. 1 to the position shown by the chain double-dashed line. Therefore, a relatively long copy sheet is guided by the lower surface of the swinging member 172 and received by the upper edge of the receiving projection 196, that is, the receiving table 192. When an intermediate length copy sheet is returned through the copy sheet return path 154, the swinging member 178 is switched from the position shown by the solid line in FIG. 1 to the position shown by the chain double-dashed line in FIG. Therefore, the copy paper of the intermediate length has the swing member 17
After passing through the upper surface of 2, the upper end edge of the receiving projection 196, that is, the pedestal 192 is guided by being guided to the lower surface of the swinging member 178. On the other hand, when a relatively short copy sheet is returned, the swing members 172 and 178 are held at the positions shown by the solid lines in FIG. Therefore, at this time, the copy sheet passes through the upper surfaces of the swinging members 172 and 178, and the return roller pair 1
It is received in the pedestal 192 by the action of 76 and 182. When the copy paper is received by the receiving table 192 and sent,
The feed roller 200 acts on the copy sheet to further feed the copy sheet to the right, and thus the leading edge of the copy sheet is brought into contact with the stop means 198 located at the operating position shown by the solid line. As a result, the progress of the copy paper is blocked and the copy paper is stopped at the required position on the copy paper resending means 190. Even if the feeding roller 200 is rotated at this point, a slip is generated between the feeding roller 200 and the copy sheet, and the copy sheet is not further advanced.

When the required number of copy sheets are returned to the copy sheet retransmitting means 190 as described above, the transport switching mechanism 114 is provided.
The lower guide member 119 and the upper guide member 120 are returned to the lowered position shown by the solid line. Then, the copy sheet resending means 190
Of the feeding roller 2 positioned at the non-acting position indicated by the chain double-dashed line and driven to rotate in a predetermined direction.
By the action of 00, the copy paper is retransmitted from the copy paper retransmitting unit 190 to the copy paper resupply path 202. The copy papers sent to the copy paper re-supply path 202 are advanced one by one through the copy paper re-supply path 202 and are again supplied to the copy paper transport path 58. As easily understood by referring to FIG. 1, such a copy sheet is turned upside down by passing through a substantially semicircular copy sheet re-supply path 202, and one side on which an image has already been formed is a bottom side. In this state, it is supplied to the copy paper transport path 58. Next, the copy paper is conveyed through the copy paper conveyance path 58. At this time, the toner image is transferred to the other surface of the copy paper, that is, the upper surface in the transfer area 18, and the toner image is fixed on the copy paper by the action of the heating and fixing roller pair 108. It is formed. Then, the copy paper is transferred to the copy paper transport path 58.
Is introduced into the transport switching path 121 through the upper roller 115 and the intermediate roller 116 of the transport switching mechanism 114, and is discharged to the tray 126 through the transport switching path 121 and the copy paper discharge path 122. In this way, a copy having images formed on both sides is obtained.

Although the present invention has been described based on the illustrated embodiments, the present invention is not limited to the embodiments. For example, in the illustrated embodiment, an outer guide plate that defines the feed reversal path is used as cooling means for cooling the outer surface of the curved portion of the copy sheet that is introduced into the feed reversal path of the feed reversal means. Although the opening is shown, the cooling means may be configured to cool the outer guide plate itself, and various modifications can be made within the scope of the technical idea of the present invention. It does not exclude.

[0023]

The electrostatic copying machine according to the present invention is constructed as described above, and is provided with the cooling means for cooling the outer side surface of the curved portion of the copy sheet introduced into the feeding reversal path.
Since the outer side surface of the curved portion of the copy paper introduced into the feeding reversal path is cooled, contraction that acts in the direction opposite to the curl direction along the curved portion occurs, and the occurrence of paper curl is suppressed. It Therefore, it is possible to prevent the occurrence of paper jam due to paper curl.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing an embodiment of an electrostatic copying machine configured according to the present invention.

FIG. 2 is an enlarged cross-sectional view of a feeding reversing unit equipped in the electrostatic copying machine shown in FIG.

FIG. 3 is a side view of the feed reversing means shown in FIG.

[Explanation of symbols]

 2: Housing 4: Stationary transparent plate 6: Original pressing member 8: Rotating drum 22: Charging corona discharger 24: Developing device 26: Transfer corona discharger 28: Peeling corona discharger 32: Residual toner removal blade 34: Optical system 36: Movable original illumination lamp 38: First movable reflecting mirror 40: Second movable reflecting mirror 42: Third movable reflecting mirror 44: Still lens assembly 46: Still reflecting mirror 48: Copy paper feeding means 58 : Copy paper transport path 80: Paper feed table mechanism 104: Transport belt mechanism 108: Heat fixing roller pair 114: Transport switching means 115: Upper roller 116: Intermediate roller 117: Lower roller 118: Transport roller mechanism 121: Transport switching path 122 : Copying paper discharging path 124: Discharging roller 125: Discharging roller 126: Receiving tray 127: Feed reversing means 128: Copying paper returning means 29: Feeding reversal path 130: Outer guide plate 131: Inner guide plate 132: Opening 133: Reverse feeding roller 135: Conveying roller 136: Reverse feeding roller operating means 141: Solenoid 150: Returning means 152: Returning controlling means 154: Copying Paper return path 190: Copy paper retransmitting means 192: Receiving stand 198: Stopping means 200: Feeding roller 202: Copying paper re-feeding path 204: Separation roller pair 208: Re-feeding roller pair 212: Re-feeding roller pair 216: Re-feeding Laura pair

Claims (2)

[Claims] 1. A copy paper transporting means for defining a copy paper transporting path, a copy paper feeding means for feeding a sheet of copy paper to the copy paper transporting path, and a copy paper feeding means arranged downstream of the copy paper transporting path. A copy paper discharge means that is provided and defines the copy paper discharge path;
Copy paper returning means for defining a copy paper returning path connected to a connecting portion between the copy paper carrying path and the copy paper discharging path, and the copy paper carried by the copy paper carrying means for the copy paper discharging path or the copy paper returning path. A transport switching mechanism for selectively guiding the copy paper to the copy paper return path, a feed reversing means for reversing the longitudinal direction of the copy paper when guiding the copy paper to the copy paper return path, and the copy paper return path In the electrostatic copying machine, the copying paper retransmitting means receives the copying paper returned through the copying paper and re-supplies the received copying paper to the copying paper conveying path. An electrostatic copying characterized by comprising a feed reversal path having a curved portion to be introduced, and a cooling means for cooling the outer side surface of the curved portion of the copy sheet introduced into the feed reversal path. Machine. 2. The feed reversal path having the curved portion is defined by an outer guide plate forming an outer side of the curved portion and an inner guide plate forming an inner side of the curved portion, and the cooling means is provided in the feeding unit. The electrostatic copying machine according to claim 1, wherein the electrostatic copying machine comprises an opening formed in an outer guide plate that defines a feed reversal path.