JP2864971B2 - Double-sided printing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-sided printing apparatus having a mechanism capable of printing on both sides of a recording medium.

[0002]

2. Description of the Related Art Conventionally, in a double-sided printing apparatus capable of printing on both sides of a sheet, when printing on both sides, first, the sheet is fed from a paper feed cassette to a printing section, and the printing is performed on one side of the sheet. After the end, in order to turn over the paper, the reversing mechanism temporarily changes the traveling direction of the paper to a direction opposite to the printing direction. After that, the paper is fed again to the printing section,
The same printing as described above is performed again on the back surface of the previously printed sheet, and the sheet is discharged to the discharge unit, thereby terminating the printing.

In this type of double-sided printing apparatus, a re-feeding conveyance section is provided to convey a sheet on which one side has been printed to the printing section again, and in order to reduce the installation area of the printing apparatus. The re-feeding conveyance section is disposed above or below the sheet cassette. Replenishment of paper to the paper feed cassette is performed by pulling out the paper feed cassette from the apparatus main body, and for paper jam processing and the like generated in the re-feeding conveyance section, the conveyance section is pulled out from the apparatus main body. The re-feeding transport unit is configured to be pulled out in the same direction as the paper feed cassette, that is, in the paper transport direction so that these operations are easily performed. Further, when a trouble such as a paper jam occurs, control is performed so that the conveyance of the paper is stopped.

[0004]

However, in this type of apparatus, a paper jam occurs near the re-feeding conveyance section, and the sheet is rolled near the exit of the reversing mechanism and near the entrance of the re-feeding conveyance section. There is a case where the conveyance of the sheet is stopped while being held by both of the rollers. In this state,
When the re-feeding transport unit is pulled out of the apparatus main body to perform the jam processing, one end of the sheet is held by the roller near the exit of the reversing mechanism, so that the sheet is torn or the sheet is left inside the apparatus. There is a problem. The present invention has been made in order to solve the above-described problem, and even if the re-feeding transport unit is pulled out of the apparatus main body to perform the jam processing, the re-feeding transport unit is held by the rollers near the re-feeding transport unit. It is an object of the present invention to provide a two-sided printing apparatus in which the used paper is not torn or the paper is not left inside the apparatus.

[0005]

According to a first aspect of the present invention, there is provided a double-sided printing apparatus which prints an image on a recording medium, and the printing unit completes one-sided printing. A reversing mechanism for reversing the front and back of the recording medium,
A re-feeding transport unit that is detachably mounted to the apparatus main body, receives the recording medium inverted by the reversing mechanism unit, and feeds the recording medium to the printing unit; A feeding roller for feeding a recording medium to the re-feeding conveyance unit, a transmission unit for transmitting a driving force to the feeding roller, and an operation of detaching the re-feeding conveyance unit from the apparatus main body. A release mechanism for releasing the connection between the feed roller and the transmission section in conjunction with the transmission mechanism.

[0006] A double-sided printing apparatus according to a second aspect of the present invention is characterized in that:
A printing unit for printing an image on a recording medium, for reversing the front and back sides of the terminated recording medium of the single-sided printing at the printing unit
A reversing mechanism provided in the apparatus main body, and a recording medium removably attached to the apparatus main body, receiving the recording medium inverted by the reversing mechanism, and feeding the recording medium to the printing section. A feeding transport unit, provided in the reversing mechanism unit,
A rotary drive is used to feed the recording medium into the refeeding conveyance section.
A first feed roller to be moved and
And the first feed is reversed by the reversing mechanism.
The recording medium conveyed by the rollers is transported for re-feeding.
Second feed roller driven to rotate to feed the feed unit
And a recording medium fed by the first feed roller or the second feed roller toward the re-feeding conveyance section.
Sensor that detects paper jams and the sensor
When a jam is detected, the reversing device on the apparatus body side
Only the first feed roller provided in the structure portion, the first
And a release mechanism for releasing the connection with the transmission unit for transmitting the rotational driving force to the feed roller .

[0007]

According to the double-sided printing apparatus of the first aspect having the above-described configuration, when printing is performed on one side of a recording medium by the printing unit and then double-sided printing is performed, the feed roller provided in the reversing mechanism is used. The recording medium is sent to the re-feeding conveyance section, and is again fed to the printing section with the recording medium turned upside down, and printing is performed on the back side of the previously printed recording medium. The feed roller is driven to rotate by the transmission of the driving force by the transmission unit. When the refeeding conveyance unit is pulled out of the apparatus main body due to occurrence of a trouble such as a paper jam or the like, the connection between the transmission roller and the transmission unit is released in conjunction with the operation, and the transmission roller is transmitted by the transmission unit. It becomes a state where it can freely rotate with respect to the rotational force. For this reason, even if the re-feeding conveyance unit is pulled out of the apparatus main body while the recording medium is held by the rollers of the reversing mechanism, the recording medium may be torn or left inside the apparatus main body. Disappears.

[0008] According to a second aspect of the invention, there is provided a surface printing apparatus.
When printing is performed on one side of the recording medium by the printing unit and then double-sided printing is performed, printing is performed on the back side of the recording medium in the same manner as described above . Sensor detects the recording medium fed to the transport unit for re-feed by the first or second feed roller. When a trouble such as a paper jam occurs, based on the ON / OFF state of the sensor, only the first feed roller is disconnected from the transmission unit that transmits the rotational driving force to the first feed roller by the release mechanism . 1 of the feed roller is in a state capable of rotating freely. Thereby, the same operation and effect as described above can be obtained.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an external perspective view of a laser printer according to the present embodiment, and FIGS. 2 to 5 are side sectional views of the printer in various operation states. In these figures, on the upper part of the laser printer main body 1 according to the present embodiment,
A printing unit (18 in FIG. 2) having a process cartridge C, a laser scanner unit D, and the like is provided.
Below the apparatus main body 1, a paper cassette P having a feeding mechanism for feeding and stacking the printing paper to the printing unit 18 while stacking and storing the printing paper is detachably provided to the apparatus main body 1. ing. A handle 2 is provided on the front surface of the sheet cassette P. When the handle 2 is grasped and pulled toward the user, the sheet cassette P is pulled out of the apparatus main body 1, thereby replenishing sheets. Is performed.

Above the paper feed cassette P, a re-feeding transport portion (formed in the form of a tray) for re-feeding the paper, which has been turned upside down in the paper reversing portion 11 described later, to the printing portion 18. Hereinafter, the tray 12 is removably mounted on the apparatus main body 1. This re-feed tray 12
A handle 13 is provided on the front surface, and the handle 13 is provided.
The tray 12 is pulled out from the apparatus main body 1 when the user pulls the tray 12 toward the user. As a result, trouble such as paper jam occurring inside the re-feed tray 12 is processed.

On the front side of the apparatus main body 1 above the re-feeding tray 12, a manual paper feed port 3 for manually feeding paper to the printing unit 18 is formed. In the vicinity of 3, a paper lower guide 4 for guiding the paper to be manually fed to the paper feed port 3 is provided. In the paper lower guide 4,
Paper side guide 5 to prevent paper from being transported at an angle
a, 5b are provided. Above the paper feed port 3 for manual paper feed, a control panel 6 for setting various print modes of the laser printer is provided. On the right side of the apparatus main body 1, a control unit 7 containing a control board for controlling each unit of the laser printer based on an input of a print mode or the like of the control panel 6 is provided.

A first paper discharge unit 8 is provided on the upper surface of the apparatus main body 1, and the paper printed by the print unit 18 is discharged with the print surface facing down (face down). Further, a paper receiving plate 9 is provided on the back of the apparatus main body 1 to form a second paper discharging unit 10, and the paper printed by the printing unit 18 is discharged with the printing surface up (face-up). It has become. A sheet reversing unit 11 for reversing the front and back of a sheet is provided below the second sheet discharging unit 10.

FIG. 2 shows details of the mechanism of the laser printer.
This will be described with reference to FIG. To feed the paper from the paper cassette P, a feed roller 21a is provided on the paper feed direction side of the paper cassette P, and a pair of feed rollers 21b opposed to the feed roller 21a are provided on the apparatus main body 1 side. I have. A sheet cassette P is placed between the pair of rollers 21a and 21b.
A half-moon-shaped paper feed roller 22 for separating and feeding paper one by one from the printer is disposed on the apparatus main body 1 side. Further, a paper path 20 for feeding the paper stored in the paper feed cassette P to the printing unit 18 is provided at the leading end of the paper feed cassette P in the paper feeding direction. When the paper feed cassette P is mounted on the apparatus main body 1, the feed rollers 21a and 21b
They are arranged in a positional relationship facing the paper path 20.

A paper detection sensor 23 and a pair of feed rollers 24a, 2
4b is arranged. The sheet guided by the sheet lower guide 4 and the sheet side guides 5a and 5b is fed into the apparatus main body 1 by a pair of feed rollers 24a and 24b when detected by the sensor 23.

A sensor 2 is located downstream of the confluence S of the sheet feeding path supplied from the sheet cassette P and the sheet feeding path supplied from the manual sheet feeding port 3 in the sheet conveying direction.
5 and a pair of registration rollers 26a and 26b are provided. By rotating or stopping the registration rollers 26a and 26b at a predetermined timing, skew correction of the sheet and timing control of the printing position are performed.

Downstream of the pair of registration rollers 26a and 26b in the sheet transport direction, a process cartridge C described later is provided.
Drum type electrophotographic photoreceptor (hereinafter referred to as drum) 30
Is disposed at a position opposed to the discharger 3 for image transfer.
1 and a static eliminator 32 are provided. Further downstream of these, a paper transport section 33 and an image fixing device 34 are provided. The process cartridge C includes the drum 30 and the charger 3
5, each process including a developing device 36, a cleaning device 37, and the like. Each process is arranged at a predetermined position in the main body cover 38 of the process cartridge C.

Above the process cartridge C, a pre-exposure lamp 39 for pre-exposing the drum 30 and a laser scanner unit D for performing scanning exposure are provided. The unit D includes a semiconductor laser 40, a rotating polygon mirror 4
1, an f-θ lens 42, a reflection mirror 43, and a scanner housing 44 for holding the same.

Downstream of the image fixing device 34 in the sheet transport direction, a sheet guide 50 for performing face-down sheet ejection to the first sheet ejection section 8, and a pair of delivery rollers 51a, 51b;
Further, a pair of feed rollers 52a and 52b for performing face-up discharge to the second paper discharge unit 10, and further, the paper discharge direction is switched to either the first paper discharge unit 8 or the second paper discharge unit 10. Flap 53 is arranged. The flap 53 is configured to rotate around a shaft 54 by a predetermined angle.

When the sheet passing through the image fixing unit 34 is guided in the direction of the sheet guide 50 by the flap 53, the sheet is ejected by the delivery rollers 51a and 51b.
Is discharged to the first paper discharge unit 8 from the printer. When guided in the direction of the feed rollers 52a and 52b, the sheet is discharged from the discharge port (not shown) to the second discharge section 10 by these rollers 52a and 52b. A paper stopper 57 is provided in the vicinity of the paper discharge port of the paper receiving plate 9 constituting the second paper discharging unit 10 so that the rear end of the paper discharged to the paper receiving plate 9 is supported.

Below the flap 53, there is provided a flap 58 for feeding the sheet passing through the image fixing unit 34 to the sheet reversing unit 11. The flap 58 is configured to rotate by a predetermined angle about an axis 59.

The sheet reversing section 11 for changing the sheet conveying direction and reversing the sheet front and back is provided with a reversing guide section 61.
a, 61b, 61c and forward / reverse rollers 62a, 62
b, and the reversing guides 61b, 61c and the forward / reverse rotation roller 62a are integrated to form a shaft 6 of the forward / reverse rotation roller 62b.
3 and is configured to rotate in a predetermined direction. The sheet reversing unit 1 is located near the reversing guide 61a.
1 is provided with a sensor 64 for detecting the entry of a sheet into the sheet 1.

Below the sheet reversing section 11, a pair of feed rollers 65a and 65b (first feed rollers) , and below the sheet reversing section 11, guide sections 66a and 66b for guiding sheets are arranged. The feed roller 65b is provided with a roller drive mechanism and a drive release mechanism, which will be described later. When the re-feed tray 12 is pulled out of the apparatus main body 1, the drive release mechanism acts to rotate the feed roller 65b. It is configured to disappear. A sensor 68 for detecting passage of a sheet is disposed near the guides 66a and 66b.

Behind the re-feed tray 12, a pair of feed rollers 70a, 70b for feeding the sheet guided by the guide portions 66a, 66b to the re-feed tray 12.
(Second feed roller) . Feed roller 7
Behind Ob, a guide portion 89 is formed integrally with the refeed tray 12. On the bottom of the re-feed tray 12,
Guide plate 7 for guiding the sheet sent to tray 12
4 are arranged.

A restricting plate 75 is provided at the distal end of the guide plate 74 on the downstream side in the sheet transport direction so as to rotate by a predetermined angle about a shaft 76. The regulating plate 75 adjusts the timing of skew and feeding of the sheet by temporarily stopping the sheet. An oblique feed roller 77 is disposed between the regulating plate 75 and the feed rollers 70a and 70b. The skew feed roller 77 is configured so that the roller is slightly inclined with respect to the traveling direction of the sheet, and corrects the position of the sheet on the guide plate 74 in the width direction by moving the sheet to one side in the width direction. .

A pair of feed rollers 78a and 78b are arranged downstream of the regulating plate 75 in the sheet conveying direction. The feed rollers 78a and 78b rotate the sheet, for which the timing of skew and feeding has been adjusted in advance by the regulating plate 75, at a predetermined timing so as to have a registration function for more accurately correcting the skew and adjusting the timing. Alternatively, a stop is performed. Control plate 75 and feed roller 78
A sensor 79 for detecting the passage of a sheet is disposed between a and 78b, and a guide plate 80 for guiding the sheet is provided downstream of the feed rollers 78a and 78b.

At the leading end of the re-feeding tray 12 in the sheet conveying direction, the sheet fed from the sheet feeding cassette P is
The paper path 81 is provided for vertically transporting the paper to the paper path 8. The sheet fed by the feed rollers 78a and 78b is guided by a guide plate 80, and is fed to an upper printing unit 18 through a sheet path 81.

The handle 13 and the feed roller 7 described above are used.
7a, 70b, guide plate 74, regulating plate 75, shaft 76, skew feed roller 77, feed rollers 78a, 78b, sensor 7
9, a guide plate 80, a paper path 81, a guide unit 89, and a mechanism and a drive source for transmitting power to each movable unit include:
It is configured integrally with the re-feed tray 12. Thus, even if a trouble such as a paper jam occurs in the re-feeding tray 12, the trouble can be dealt with by pulling out the tray 12 from the apparatus main body 1.

Next, a series of operations from image recording to sheet discharge will be described with reference to FIGS. FIG. 2 shows the case where the paper is discharged to the first paper discharge unit 8, FIG. 3 shows the case where the paper is discharged to the second paper discharge unit 10, and FIG.
FIG. 5 shows a state in which the paper is conveyed to the re-feed tray 12 when the paper is conveyed to the tray 12. In response to the image recording start signal, first, the half-moon-shaped paper feed roller 22 is intermittently rotated by one rotation or a predetermined plurality of rotations in the paper feeding direction at each predetermined paper feeding timing. Sheets are separated one by one, and the feed rollers 21a, 21b
Is fed upward. When the sensor 25 detects the sheet, the leading end of the sheet is temporarily held by the registration rollers 26a and 26b in a stopped state, and then the registration rollers 26a and 26b
The sheet is conveyed between the drum 30 and the image transfer discharger 31 by being rotationally driven at a predetermined timing synchronized with the detection timing.

Simultaneously with the feeding of the sheet, the drum 30 is driven to rotate at a predetermined peripheral speed in the direction of an arrow about an axis (not shown) by an image recording start signal. In the course of the rotation, the drum 30 is subjected to the entire surface pre-exposure by the pre-exposure lamp 39 on the peripheral surface thereof, and then to the positive or negative uniform charging by the charger 35. Subsequently, the exposure portion 30a on the drum 30 is subjected to laser beam scanning exposure by the laser scanner unit D, so that an electrostatic latent image of a target image is formed on the peripheral surface.

In the laser beam scanning exposure by the laser scanner unit D, first, a laser beam modulated according to a time-series electric pixel signal of a target image is output from the semiconductor laser 40 to the rotary polygon mirror 41.
Next, the scanning speed for the rotation angle of the rotating polygon mirror 41 is
The light is converted into a substantially constant speed by the f-θ lens 42,
The output direction is changed via 3 and the laser beam is scanned and exposed in the drum generatrix direction on the surface of the drum 30.

The electrostatic latent image formed on the surface of the drum 30 is developed with toner by a developing device 36, and the image transferring discharge device 31 is used.
To the position. Then, after the toner development, the toner image is sequentially transferred onto the sheet surface conveyed between the drum 30 and the transfer discharger 31 in synchronization with the rotation of the drum 30. The sheet to which the toner image has been transferred is sequentially separated from the surface of the drum 30 by the action of the charge remover 32, and is conveyed to the image fixing unit 34 via the sheet conveying unit 33. In the image fixing device 34, the image is fixed by melting the toner by heat. The surface of the drum 30 from which the paper has been separated is cleaned by the cleaning device 37, and is repeatedly provided for image formation.

By the above operation, an image is recorded on one side of the sheet, and in the case of single-sided printing, a discharging operation is performed next. In the present embodiment, regardless of whether or not to perform double-sided printing, a sheet can be discharged to one of the first paper discharge unit 8 and the second paper discharge unit 10 by the user's selection. The discharge position is determined by the set positions of the flaps 53 and 58. The switching of the flaps 53 and 58 is performed manually or by a drive device (not shown) when the user selects the discharge position by the control panel 6 or the like.

When the paper is discharged to the first paper discharge section 8, the flaps 53 and 58 are set at the positions shown in FIG. 2 manually or by a driving device (not shown). Thus, the sheet that has passed through the image fixing device 34 is guided to the upper surface of the flap 53, guided upward along the sheet guide 50, and discharged to the first sheet discharge unit 8 by the feed rollers 51 a and 51 b.

When the paper is discharged to the second paper discharge unit 10, the flaps 53 and 58 are set at the positions shown in FIG. 3 manually or by a driving device (not shown). This allows
The sheet that has passed through the image fixing device 34 is guided by the lower surface of the flap 53 and the upper surface of the flap 58,
a, 52b, these rollers 52a, 5b
The sheet is discharged to the second sheet discharge section 10 by 2b.

In the case of double-sided printing, the sheet after the single-sided printing is first conveyed to the sheet reversing unit 11. In this case, the flaps 53 and 58 are set to the positions shown in FIG. 4 manually or by a driving device (not shown). Thus, the sheet that has passed through the image fixing device 34 is guided to the lower surface of the flap 58 and guided to the sheet reversing unit 11. Here, the sheet reversing operation in the sheet reversing unit 11 will be described with reference to FIGS. The sheet guided to the lower surface of the flap 58 and guided by the reversing guide 61a is further transported between the reversing guides 61b and 61c. Under the above circumstances, the rotation of the forward / reverse rollers 62a and 62b is controlled such that the sheet conveyed from the image fixing device 34 is further conveyed to the back of the sheet reversing unit 11, whereby the sheet is further conveyed. It is transported to the back.

The forward / reverse rollers 62a and 62b
After a lapse of a predetermined time from when the sheet 4 detects the last end of the sheet, its driving is temporarily stopped. At this time, the sheet is in a state where the vicinity of the final end thereof is nipped by the forward / reverse rollers 62a, 62b. In this state, the reversing guides 61b, 61c and the forward / reverse roller 62a are integrated as shown in FIG. And is rotated about the shaft 63. When rotated, the rotation of the forward / reverse rollers 62a and 62b is controlled so that the sheet is conveyed in a direction opposite to the above-described direction, whereby the sheet is conveyed in the direction of the feed rollers 65a and 65b. You.

The paper, the transport direction of which has been changed by the above operation, is subsequently transported to guide portions 66a, 66b by feed rollers 65a, 65b. The paper is the guide 66
a and 66b, the sensor 68 detects the leading edge and the trailing edge of the sheet. Then, the occurrence of a trouble such as a paper jam is detected by comparing the time at which the paper is detected with a set time determined from the timing at which the predetermined paper inversion operation is performed.

The paper guided by the guides 66a and 66b is further guided by a guide 89, and is fed by a feed roller 70.
The sheet is conveyed to the re-feed tray 12 by a and 70b.
The sheet conveyed to the re-feed tray 12 is guided by a guide plate 74.
Is guided to the skew feed roller 77 to correct skew. Thereafter, the sheet is conveyed by the skew feed roller 77 and is brought into contact with the regulating plate 75, and the leading end in the feeding direction is regulated by the regulating plate 75, thereby further correcting skew. The sheet is released from the stopped state and transported by the rotation of the regulating plate 75 about the shaft 76 at a predetermined timing.

When the sensor 79 detects the entrance timing of the leading end of the sheet, the feed roller 78 in the stopped state is detected.
The sheets a and 78b are driven to rotate at a predetermined timing, and the sheet fed by the feed rollers 78a and 78b is guided by the guide plate 80, and is conveyed upward through the sheet path 81. Then, an image is recorded on the back surface of the sheet conveyed to the printing unit 18 by the registration rollers 26a and 26b by the same operation as the above-described front surface printing. Image recording is controlled by a control system (not shown), and predetermined images are sequentially formed.

FIG. 6 is a diagram showing the structure of the re-feed tray 12. As shown in FIG. The re-feed tray 12 is integrally formed with a mechanism for transmitting power to each movable unit, a motor 91 as a drive source, a connector 92, a gear train 93, a timing clutch 94, and the like. A connector connection portion is arranged at a position corresponding to the connector portion 92 on the device main body 1 side. Control plate 75, skew feed roller 77, feed rollers 78a, 78
b, the sensor 79 and the like are driven at appropriate timing by receiving a control signal or the like from the control unit 7 of the apparatus main body 1 or a drive current of the motor 91 via the connector unit 92. Is fed back to the control unit 7 to be controlled appropriately. The transmission of the rotational driving force from the motor 91 is performed by a gear train 93, a timing clutch 94, and the like.

The refeeding tray 12 is provided with guide projections 95 on both sides thereof. When the handle 13 on the front of the refeed tray 12 is grasped and pulled toward the user, the guide projections 95 are provided. Is guided by a guide portion (not shown) of the apparatus main body 1 and can be pulled out from the apparatus main body 1 as shown in FIG.

Next, the feed roller 65 which is a feature of the present invention is described.
The drive mechanism and the drive release mechanism b will be described with reference to FIG. The pair of feed rollers 65a and 65b are for feeding a sheet to the re-feeding tray 12, and are provided below the sheet reversing unit 11. Refeed tray 12
Behind, an L-shaped arm member 101 is supported by a shaft 102 disposed on one side thereof.
It is configured to be rotatable around. An idle gear 103 is provided on the other side of the arm member 101, and a contact member 104 formed of an elastic body or the like is provided on a surface facing the back surface of the re-feed tray 12. The arm member 101 having the above configuration has a spring 10 having one end arranged in the apparatus main body 1.
5, a clockwise rotational force about the shaft 102 is constantly applied.

A gear 10 is provided on one side of the feed roller 65b.
6 are arranged. Further, the apparatus main body 1 is provided with a gear 107 driven by a driving device (not shown) disposed in the apparatus main body 1 or the sheet reversing section 11.
When the refeed tray 12 is mounted on the apparatus main body 1, the gears 106 and 107 are engaged with and connected to the idle gear 103. When the refeed tray 12 is pulled out of the apparatus main body 1, the idle The gear 103 is configured to be disengaged from the gear 103 so as not to be connected.

As shown in FIG. 7A, when the refeed tray 12 is mounted on the apparatus main body 1, the refeed tray 12
Abuts against the contact member 104, a counterclockwise rotational force about the shaft 102 is applied to the arm member 101, and the idle gear 103 is held in a state of meshing with the gears 106 and 107. Thus, the gear 106 and the gear 107 are connected via the idle gear 103, and the driving force from the apparatus main body 1 is transmitted to the gear 106, and the feed roller 65b is driven to rotate.

As shown in FIG. 7B, when a trouble such as a paper jam occurs, the refeed tray 12 is moved to the main assembly 1 of the apparatus.
When the arm member 101 is pulled out, the arm member 101 rotates clockwise about the shaft 102 by the urging force of the spring 105. Thereby, the meshing between the idle gear 103 and the gears 106 and 107 is released, and the driving force from the apparatus main body 1 side is reduced to the gear 106.
And the feed roller 65b can freely rotate with respect to the rotational force from the apparatus main body 1 side.

As described above, when the re-feed tray 12 is pulled out of the apparatus main body 1, the engagement between the idle gear 103 and the gears 106 and 107 is released in conjunction with the operation, and the feed roller 65b is moved to the main body of the apparatus. It is possible to freely rotate with respect to the rotational force from one side. As a result, while the paper is held by both the feed rollers 65a and 65b and the feed rollers 70a and 70b of the re-feed tray 12, the conveyance of the paper is stopped due to the occurrence of a trouble such as a paper jam. Even if the re-feed tray 12 is pulled out, the sheet is released from being held by the feed rollers 65a and 65b, and is held by the feed rollers 70a and 70b without being torn or left in the apparatus main body 1. While being held, it is pulled out to the front of the apparatus main body 1 together with the re-feed tray 12, and is removed.

Next, a second embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In the second embodiment, the drive mechanism and the drive release mechanism of the feed roller 65b are different from those of the first embodiment. A gear 106 is provided on one side of the feed roller 65b.
Is arranged. In addition, the apparatus main body 1 includes the apparatus main body 1.
Alternatively, a gear 107 driven by a driving device (not shown) disposed in the sheet reversing unit 11 is provided. Further, these gears 106,
An idle gear 103 connectable to 107 is arranged on the apparatus main body 1 side.

Gear 106, idle gear 103, gear 1
When the clutch 108 is turned on, the clutches 07 are connected to each other, the driving force from the apparatus main body 1 is transmitted to the gear 106, and the feed roller 65b is rotated. When the clutch 108 is turned off, the idle gear 103 is not rotated with respect to the rotation of the gear 107, so that the driving force from the apparatus main body 1 side is not transmitted to the gear 106, and the feed roller 65b is It can rotate freely against the rotational force from the side.

The ON / OFF switching of the clutch 108 is performed in conjunction with the movement of the re-feed tray 12. That is, on the side of the apparatus main body 1 behind the re-feeding tray 12,
A switch 109 for detecting whether the re-feed tray 12 is mounted on the apparatus main body 1 is provided, and FIG.
As shown in FIG. 8, when the re-feed tray 12 is mounted on the apparatus main body 1, the switch 109 is turned ON, and FIG.
As shown in the figure, when the re-feed tray 12 is pulled out from the apparatus main body 1, the switch 109 is turned off, and based on the ON / OFF state of the switch 109, the clutch 10 is turned off.
8 is turned ON / OFF.

FIG. 9 shows the clutch 1 when a jam is detected.
08 shows the switching operation. First, when the apparatus main body 1 detects a paper jam, the driving of all motors related to paper conveyance is stopped (S1). Next, the switch 109 is set to O
It is checked whether the FF, that is, the re-feed tray 12 has been pulled out (S2). When it is detected that the tray 12 has been pulled out, the clutch 108 is turned off (S3), and the feed roller 65b is turned by the rotational force from the apparatus main body 1 side. To rotate freely. Thereby, the paper is fed to the feed rollers 65a and 65b.
Even if the re-feed tray 12 is pulled out while being held by both the feed rollers 70a and 70b of the re-feed tray 12, the sheet is released from being held by the feed rollers 65a and 65b, so that the sheet is torn. It is pulled out together with the re-feeding tray 12 to the front of the apparatus main body 1 without being left in the apparatus main body 1 or being retained by the feed rollers 70a and 70b, and is removed. If the refeed tray 12 is not pulled out in S2, another jam detection process is performed (S6).

Next, the switch 109 is turned on, that is,
It is checked whether the refeed tray 12 is mounted on the apparatus main body 1 (S4). The clutch 108 is in an OFF state until it is mounted. When the refeed tray 12 is mounted, the clutch 108 is turned ON. (S5), the driving force of the apparatus body 1 is transmitted to the feed roller 65b, and the process proceeds to another process. The attachment of the re-feed tray 12 to the apparatus main body 1 may be detected by a connector 92 provided on the re-feed tray 12.

Next, a modification of the operation at the time of jam detection will be described with reference to FIG. The control method of the drive mechanism and the drive release mechanism of the feed roller 65b is different from the above. That is, in the above, the clutch 108 is turned ON / OFF based on whether or not the refeed tray 12 is pulled out of the apparatus main body 1.
The drive mechanism and the drive release mechanism are controlled by being turned OFF. In this example, the clutch 108 is turned ON / OFF based on the ON / OFF state of the sensor 68 that detects the sheet fed from the sheet reversing unit 11. It is controlled by turning it off.

As a sensor for detecting a sheet, the apparatus main body 1
As shown in FIG. 2, a sensor 25 for detecting a sheet fed to the printing section 18, a sensor 64 for detecting a sheet fed to the sheet reversing section 11, and a sensor for detecting the sheet fed from the sheet reversing section 11. 68, tray 1 for re-feeding
A sensor 79 for detecting the sheet sent out from the second unit 2;
A sensor (not shown) for detecting the sheet fed to the image fixing device 34 is provided. The apparatus body 1 detects ON / OFF signals of these sensors, and compares this timing with a predetermined timing by the control unit 7 to detect a paper jam.

When the apparatus main body 1 detects a paper jam, the driving of all the motors related to paper conveyance is stopped (S1).
1). Next, it is checked whether the sensor 68 is ON, that is, whether the sheet remains at the position of the sensor 68 (S12).
When the sensor 68 is ON, the clutch 108 is turned OFF (S13), and the feed roller 65b rotates freely with respect to the rotational force from the apparatus main body 1 side. As a result, the sheet is released from being held by the feed rollers 65a and 65b, so that even if the re-feed tray 12 is pulled out of the apparatus main body 1, the sheet is not torn or left in the apparatus main body 1. While being held by the feed rollers 70a and 70b, the sheet is pulled out to the front of the apparatus main body 1 together with the re-feed tray 12 and removed. If the sensor 68 is not ON in S12, it is not the jam of the same part,
Other jam processing is performed (S18).

Next, the switch 109 is changed from ON to OFF.
(S14), the switch 109 is turned from OFF to O
N (S15), whether the sensor 68 is OFF (S1
By examining item 6), it is determined whether the re-feed tray 12 is once pulled out of the apparatus main body 1 and then mounted, and whether the paper near the feed roller 65b has been removed. When the re-feed tray 12 is detached from the apparatus main body 1 and the paper is removed (NO in S14, YES in S15,
(YES in S16), it is determined that the jam processing has been completed, the clutch 108 is turned on (S17), and the feed roller 65
The driving force of the apparatus main body 1 is transmitted to b, and the process proceeds to another process.

[0056]

As described above, according to the duplex printing apparatus of the first aspect of the present invention, when a trouble such as paper jam occurs,
When the re-feeding transport unit is pulled out of the apparatus main body, the connection between the feed roller and the transmission unit is released in conjunction with the operation,
The feed roller can freely rotate with respect to the rotational force transmitted by the transmission unit. With this configuration, even when the re-feeding conveyance unit is pulled out of the apparatus main body in a state where the recording medium is held by the rollers of the reversing mechanism, the recording medium is torn,
Alternatively, it is not left behind in the apparatus main body.

According to the double-sided printing apparatus of the second aspect, when a trouble such as a paper jam occurs, the first and second printing apparatuses are set.
When it is determined that the paper has jammed based on the ON / OFF state of a sensor that detects a recording medium fed to the re-feeding conveyance unit by the second feed roller, the first feeding is performed. Ri rollers only being released connection between the transmitting portion, the first feed roller can rotate freely. Thereby, the same effect as above can be obtained.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a laser printer according to a first embodiment of the present invention.

FIG. 2 is a side sectional view of the same printer, showing a state in which paper is discharged to a first paper discharge unit.

FIG. 3 is a side sectional view of the printer, showing a state where a sheet is discharged to a second sheet discharge unit.

FIG. 4 is a side sectional view of the printer, showing a state in which a sheet is transported to a sheet reversing unit.

FIG. 5 is a side sectional view of the printer, illustrating a state in which a sheet is transported to a re-feeding transport unit.

FIG. 6 is a perspective view of a re-feeding transport unit of the printer.

FIGS. 7A and 7B are diagrams illustrating a drive mechanism and a drive release mechanism of a feed roller of the printer, wherein FIG. 7A illustrates a state in which a re-feeding conveyance unit is mounted on the apparatus main body, and FIG. 5 shows a state in which the transport unit is pulled out of the apparatus main body.

8A and 8B are diagrams showing a drive mechanism and a drive release mechanism of a feed roller of a printer according to a second embodiment, wherein FIG. 8A shows a state in which a re-feeding conveyance unit is mounted on the apparatus main body, and FIG. The state where the re-feeding conveyance unit is pulled out from the apparatus main body is shown.

FIG. 9 is a flowchart showing the operation of the mechanism according to the second embodiment when a jam is detected.

FIG. 10 is a flowchart illustrating an operation when a jam is detected according to a modified example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser printer main body 11 Paper reversing part 12 Re-feeding conveyance part 18 Printing part 65a, 65b Feed roller 68 Sensor 101 Arm member 103 Idle gear 104 Contact member 105 Spring 106, 107 Gear 108 Clutch 109 Switch

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B65H 7/06 B41J 3/00 B41J 13/00 B65H 85/00 G03G 15/00 526

Claims (2)

(57) [Claims] 1. A printing unit for printing an image on a recording medium, a reversing mechanism for reversing the front and back of the recording medium on which printing on one side has been completed by the printing unit; A re-feeding transport unit that is mounted and receives the recording medium inverted by the reversing mechanism unit and feeds the recording medium to the printing unit; and the re-feeding transport unit provided in the reversing mechanism unit. A feed roller for feeding a recording medium into the unit, a transmission unit for transmitting a driving force to the feed roller, and the feed roller in conjunction with an operation of detaching the re-feeding conveyance unit from the apparatus main body. A double-sided printing apparatus, comprising: a release mechanism that releases a connection with the transmission unit. 2. A printing unit for printing an image on a recording medium, a reversing mechanism provided on an apparatus main body for reversing the front and back of the recording medium on which printing on one side has been completed by the printing unit, A re-feeding transport unit that is detachably attached to the main body, receives the recording medium inverted by the reversing mechanism unit, and feeds the recording medium to the printing unit; A first feed roller that is rotatably driven to feed a recording medium into the re-feeding conveyance unit, and a first feeding roller that is provided in the re-feeding conveyance unit,
Note that the sheet is reversed and conveyed by the first feed roller.
Rotary drive to feed recording media into its refeeding transport
Di second feed roller and the first feed roller or the second recording medium to be fed toward the conveyance unit for feeding the re-feeding by a feed roller that is
A sensor for detecting a jam, and when the sensor detects a jam on the recording medium,
Only the first feed roller provided in the reversing mechanism of the apparatus main body transmits a rotational driving force to the first feed roller.
A double-sided printing apparatus, comprising: a release mechanism that releases a connection with a reaching transmission unit.