JPH06219651A - Image recording device - Google Patents

Abstract

PURPOSE:To enable both surface recording even if a paper supplying device is provided with an sheet housing container having only one stage without increasing a cost and making an image recording device large. CONSTITUTION:A laser printer is provided with a paper resupplying passage 29 for returning a sheet whose one side is recorded into a paper supplying cassette 19 and an electric control means 18 for releasing pressing of a placed sheet S on a paper supplying roller 20 when a sheet whose one surface is recorded is returned into the paper supplying cassette 19 through the paper resupplying passages so as to reverse the paper supplying roller 20, while for reversedly resupplying the sheet whose one surface is recorded by normally rotating the paper supplying roller 20 again when the sheet whose one surface is recorded is returned into the paper supplying cassette 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a printer, a copying machine,
The present invention relates to an image recording device for recording on a sheet by printing, transferring, copying, printing, etc., such as a facsimile and a printing machine. Specifically, the stacked sheets to be stored in the sheet storage container are pressed against the sheet feeding roller, the stacked sheets are separated and fed one by one by the rotation of the sheet feeding roller, and the discharged sheet is recorded and discharged. Recording device

[0002]

2. Description of the Related Art Conventionally, in this type of image recording apparatus,
There is a sheet in which recording is performed on one side of a fed sheet, then inverted and re-fed, and recording is performed on the other side. In order to enable such double-sided recording, for example, in a conventional laser printer, an independent double-sided unit is assembled, and a double-sided unit is attached in place of the first-stage sheet storage container of the multi-stage sheet feeding device. The unit reversed the sheet after single-sided recording and re-fed it.

[0003]

However, in the case of assembling an independent double-sided unit, since it is provided independently, there is a problem that the cost becomes high and the whole size becomes large.
Further, in the case of providing the double-sided unit instead of the sheet storage container, the double-sided unit must be separately provided, so that the cost becomes high and the sheet feeding device is attached to the one having only one sheet storage container. There was a problem that I could not do.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to enable double-sided recording without increasing the cost or increasing the size and even if the sheet feeding device has only one sheet storage container.

[0005]

Therefore, the present invention provides
For example, as shown in the illustrated embodiment below, the paper feed cassette 1
A stacked sheet S in a sheet storage container such as 9 is pressed against the sheet feeding roller 20, the stacked sheet S is separated and sent out one by one by the rotation of the sheet feeding roller 20, and recording is performed on the sent out sheet. In an image recording apparatus that ejects a single-sided recording sheet, a sheet re-feeding path 29 for returning the sheet after single-sided recording into the sheet storage container and a sheet after the single-sided recording through the re-feeding path 29 When the pressing of the stacked sheets S against the paper feed roller 20 is released and the paper feed roller 20 is rotated in the reverse direction, the paper feed roller 20 is returned when the sheet after the one-sided recording is returned to the sheet storage container. And an electric control unit 18 for re-forwarding and reversing and re-feeding the sheet after the one-sided recording.

According to a second aspect of the present invention, for example, as shown in the following illustrated embodiment, in the image recording apparatus according to the first aspect, when the sheet after the one-sided recording is returned to the sheet storage container, The sheet is detected by a sensor such as the second sensor 33, and the reverse rotation of the paper feed roller 20 is stopped by the electric control unit 18 based on the detection result of the sensor.

According to a third aspect of the present invention, for example, as shown in the following illustrated embodiment, in the image recording apparatus of the first aspect, the side fence 41 inside the sheet storage container is used.
The guide portion 41a for guiding the sheet after the one-sided recording to be returned into the sheet storage container is provided at the front end of 41.

[0008]

When the double-sided recording is performed, the electric control means 1
In step 8, the pressing of the stacked sheets S against the sheet feeding roller 20 is released, the sheet feeding roller 20 is reversed, and the sheet re-feeding path 2
The sheet after single-sided recording is returned to the sheet storage container through 9. Then, when the sheet after single-sided recording is returned to the inside of the sheet storage container, the electric control means 18 causes the sheet feeding roller 20 to rotate normally again, and the sheet after single-sided recording is reversed and re-fed. To do.

According to the second aspect of the present invention, when the sheet after the one-sided recording is returned to the sheet storage container, the sheet is detected by the sensor, and the electric control means 18 is based on the detection result of the sensor. The reverse rotation of the paper feed roller 20 is stopped.

According to the third aspect of the present invention, when the sheet after one-sided recording is returned to the inside of the sheet storage container, the sheet is guided by the guide portions 41a and 41a.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall schematic configuration diagram of an internal mechanism in a laser printer which is an embodiment of the present invention. Reference numeral 10 in the figure denotes the apparatus main body. A drum-shaped photoconductor 11 is provided in the main body 10 of the apparatus at substantially the center thereof. Around the photoconductor 11, in the drive direction indicated by the arrow,
A charging device 12, a developing device 13, a transfer device 14, and a cleaning device 15 are arranged. Further, an optical writing device 16 is arranged above the charging device 12 and the cleaning device 15, and a fixing device 17 is arranged on the left side of the photoconductor 11 in the figure.
An electric control unit 18 is provided between the fixing unit 17 and the fixing unit 17. On the other hand, a paper feed cassette 19 is detachably attached to the lower part inside the apparatus body 10.

A paper feed roller 20 is provided on the upper right side which is the front end side of the paper feed cassette 19, and a push-up lever whose one end is biased upward by a spring or the like is provided on the lower side of the paper feed cassette 19. 21 is provided. Further, above the paper feed cassette 19, the stacked sheets S are separated and sent out one by one by the rotation of the paper feed roller 20, conveyed to the lower side of the photoconductor 11, and further conveyed to the fixing device 17. A transport path 22 is provided. Between the paper feed roller 20 and the photoconductor 11 on the transport path 22,
A pair of transport rollers 23 and a pair of registration rollers 24 are sequentially provided in the direction of the photoconductor 11.

On the exit side of the fixing device 17, a paper discharge roller is provided.
A pair of rollers 25 is provided, and a sheet discharge path 27 is provided between the pair of sheet discharge rollers 25 and a sheet discharge tray 26 provided outside the apparatus main body 10. The discharge roller pair is provided at the exit of the sheet discharge path 27. 28 is provided. The sheet after single-sided recording is returned between the exit side of the pair of discharge rollers 25 in the discharge path 27 and the exit side of the paper feed roller 20 in the transport path 22 into the paper feed cassette 19 for refeeding. Road 2
9 is provided, and the re-feeding path 29 is provided with conveying roller pairs 30 and 31 in the direction of the sheet feeding roller 20 at appropriate intervals. A first sensor 32 for detecting the sheet is provided between the pair of conveying rollers 30 and 31, and a second sensor 33 for detecting the rear end of the sheet is provided at the exit side of the conveying path 22. Set up.

A rotatable switching claw 34 is provided at a branch portion between the re-feeding path 29 and the discharge path 27, and the re-feeding path 29 is provided.
A shutter 35 that closes the opening of the re-feeding path 29 is provided at the confluence of the sheet feeding path 22 and the conveying path 22. The shutter 35 is formed of a thin elastic plate, and only a part of the shutter 35 is attached to the edge of the opening to close the entire surface of the opening so that it can be opened by elastic deformation when the sheet is conveyed from the sheet refeed path 29.

On the other hand, the above-mentioned paper feed cassette 19 is box-shaped as shown in FIG. 2, and the upper surface of the side wall 19a on the front side thereof is formed into an inclined surface facing the inside of the paper feed cassette 19 and its A separation roller 40, a part of which is exposed, is provided at a substantially central position. Further, on the bottom surface of the paper feed cassette 19, a pair of side fences 41, 41 parallel to the left and right side walls 19b, 19b and an end fence 42 in the direction orthogonal thereto are provided. Guide portions 41a and 41a formed on the inclined surface where the distance between the side fences 41 and 41 gradually increases are provided at the front ends of the side fences 41 and 41 on the sheet feeding side.

A sheet is stored in the paper feed cassette 19, and both sides and the rear end of the sheet are fed by side fences 41 and 41, respectively.
41 and the end fence 42, and as shown in FIG. 1, the bottom plate 43 rotatably attached to the front side from the center is pushed up by the push-up lever-21, and the upper surface of the stack sheet S is fed by the paper feed roller 20. Press against.

In the laser printer thus constructed, the rotation of the photoconductor 11 in the clockwise direction in the drawing is accompanied by
The surface of the photoreceptor 11 is uniformly charged by the charger 12, and then the laser light is irradiated by the optical writer 16 to form an electrostatic latent image, and the toner is attached to the developer 13 to form a visible image. .

On the other hand, from the paper feed cassette 19 to the paper feed roller 2
At 0, the sheet is sent out and the sheet feeding roller 20 and the separation roller 4
0 and 1 are separated one by one, and the conveying roller pair 23 is used to convey the conveying path 22.
The paper is conveyed inside and abutted against the pair of registration rollers 24 to be stopped. Thereafter, the registration roller pair 24 is rotated in synchronization with the rotation of the photoconductor 11 to convey the sheet, and the transfer device 14 transfers the visible image on the surface of the photoconductor 11 to the sheet. Then, the sheet after the image transfer is conveyed to the fixing device 17, and the transfer device fixes the transferred image. On the other hand, the surface of the photoconductor 11 after the image transfer is cleaned by the cleaning device 15.

In the case of normal single-sided recording only, the sheet after the image fixing is sent out into the sheet discharge path 27 by the sheet discharge roller pair 25, and is discharged onto the sheet discharge tray 26 by the sheet discharge roller 28. Discharge.

When performing double-sided recording, the switching claw 34
The sheet after single-sided recording is sent to the sheet re-feeding path 29 by the discharge roller 25, and is conveyed toward the sheet feeding cassette 19 by the pair of conveying rollers 30 and 31. At this time, as shown in FIG. 3, the sheet is detected by the first sensor 32, the signal is sent to the electric control means 18, and the electric control means 18 controls the drive means 44. The feed roller 20 is reversely rotated by changing the meshing of the gears. Then,
The separation roller 40 is rotated with the paper feed roller 20. Next, the electric control means 18 actuates the driving means 45 such as a solenoid to pull down the push-up lever 21 to separate the upper surface of the stacking sheet S on the bottom plate 43 from the paper feed roller 20. Then, the sheet in the re-feeding path 29 is guided by the switching guide 35.
While being elastically deformed, the sheet is conveyed to the sheet feeding roller 20 through the confluence with the conveying path 22, and is fed into the sheet feeding cassette 19 by the sheet feeding roller 20. At this time, the guide portions 41a and 41a of the side guides 41 and 41 guide both sides of the sheet to smoothly return them to the inside of the paper feed cassette 19.

When the sheet comes near the second sensor 33, the rear end of the sheet is detected by the second sensor 33, and the rear end of the sheet becomes the paper feed roller 20. When it reaches between the separation rollers 40, the electric control means 18 controls the driving means 44 to stop the reverse rotation of the sheet feeding roller 20, and the rear end of the sheet is separated from the sheet feeding roller 20. It is clamped between rollers 40. And
The operation of the drive means 45 is stopped by controlling by the electric control means 18, the bottom plate 43 is pushed up by the push-up lever-21, and the sheet upper surface after one-side recording is pressed against the paper feed roller 20. And
Immediately after that, the electric control means 18 controls the driving means 44 to rotate the paper feed roller 20 in the normal direction, send the sheet into the conveying path 22 and perform recording on the other surface of the sheet. , Ejection roll
It is sent out into the paper discharge path 27 by a pair of rollers 25, and the discharge roller 28
The sheet is discharged onto the sheet discharge tray 26.

[0022]

Therefore, according to the present invention, when performing double-sided recording, the electric control means releases the pressing of the stacked sheets against the paper feed roller and reverses the paper feed roller.
The single-sided printed sheet is returned to the sheet storage container through the re-feeding path. Then, when the sheet after single-sided recording is returned to the sheet storage container, the paper feed roller is normally rotated again by the electric control means, and the sheet after single-sided recording is reversed and re-fed, so that the cost is increased. 1 in paper feeding device without increasing the size
Double-sided recording is possible even if there is only a multi-tiered sheet storage container.

According to the second aspect of the present invention, when the sheet after one-sided recording is returned to the sheet storage container, the sheet is detected by the sensor, and the electric control means detects the sheet feed roller based on the detection result of the sensor. Since the reverse rotation is stopped,
The sheet can be reliably re-fed by gripping the sheet with a sheet feeding roller.

According to the third aspect of the present invention, in the case of double-sided recording, when the sheet after single-sided recording is returned into the sheet storage container through the re-feeding path, the sheet is guided by the guide portion. Since it is guided, it can be smoothly fed into the sheet storage container.

[Brief description of drawings]

FIG. 1 is an overall schematic configuration diagram of an internal mechanism in a laser printer which is an embodiment of the present invention.

FIG. 2 is a perspective view of a paper feed cassette used in the laser printer.

FIG. 3 is a block diagram of an electric drive system that works during double-sided recording.

[Explanation of symbols]

 18 Electric Control Means 19 Paper Feed Cassette (Sheet Storage Container) 20 Paper Feed Roller 29 Refeeding Path 33 Second Sensor (Sensor) 41 Side Fence 41a Guide Part S Loading Sheet

Claims (3)

[Claims] 1. A stacked sheet in a sheet storage container is pressed against a sheet feeding roller, the stacked sheet is separated and sent out one by one by rotation of the sheet feeding roller, and the sent out sheet is recorded and discharged. In the image recording apparatus, a sheet re-feeding path for returning the sheet after single-sided recording into the sheet storage container, and a sheet re-feeding roller for returning the sheet after single-sided recording through the re-feeding path into the sheet storage container While releasing the pressing of the stacked sheets and rotating the paper feed roller in the reverse direction, when the sheet after the one-sided recording is returned to the sheet storage container, the paper feed roller is rotated again in the forward direction and the one-sided recording is performed. And an electric control means for reversing and re-feeding the sheet. 2. When returning the sheet after the one-sided recording to the inside of the sheet storage container, the sheet is detected by a sensor, and the electric control means stops the reverse rotation of the sheet feeding roller based on the detection result of the sensor. The image recording apparatus according to claim 1, wherein 3. The image recording apparatus according to claim 1, wherein a guide portion for guiding the one-sided recording sheet to be returned into the sheet storage container is provided at an end of a side fence in the sheet storage container.