JPH041663A - Both-surface unit for image forming device - Google Patents

Abstract

PURPOSE:To easily remove recording paper after jam occurrence by switching a switching means to the side of a 2nd conveyance path when a jam occurs, and discharging the recording paper to the other unit without refeeding paper. CONSTITUTION:The path from a fetching roller 101 to a paper refeeding part 108 forms a 1st conveyance path for refeeding recording paper after one-surface printing and the path from the take-in roller 101 to a lower discharging roller 111 forms the 2nd conveyance path for discharging the recording paper after jam occurrence to the other unit. The 1st and 2nd conveyance paths are switched by the switching means 112 in case of jam occurrence and the recording paper after single surface printing is discharged to the other unit. Consequently, the number of sheets of recording paper remaining on the conveyance path in the device at the time of jam occurrence is decreased and recording paper removing operation is facilitated.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a duplex unit of an image forming apparatus that is provided with a conveyance path for refeeding recording paper that has been printed on one side in order to print on both sides of the recording paper. Regarding.

[Conventional technology]

Conventional image forming devices such as electrophotographic devices and laser printers are equipped with a duplex unit that is equipped with a conveyance path that refeeds recording paper that has already been printed on one side in order to print on both sides of the recording paper. Many have been proposed.

When performing double-sided printing processing in such an image forming apparatus, an image on a photosensitive drum is printed on one side of a fed recording paper, and then the printed recording paper is reversed and conveyed to a duplex unit.

The recording paper that has been printed on one side and is transported to the duplex unit is stored in the intermediate tray of the duplex unit and aligned, then the paper is fed again from the intermediate tray and printing is performed on the back side, and when the printing on both sides is completed, Expelled from the device.

[Problem to be solved by the invention]

The duplex unit of the conventional image forming apparatus described above is configured to simply store and refeed recording paper that has already been printed on one side, so it is not possible to perform double-sided printing while continuously transporting recording paper. When a jam occurs at a location, most of the recording paper, including the jammed recording paper, remains in the apparatus, posing the problem that the task of removing the recording paper becomes extremely troublesome.

The present invention has been made in view of the above, and an object of the present invention is to simplify the recording paper removal process after a jam occurs.

[Failure to solve the problem]

In order to achieve the above-mentioned object, the present invention provides a duplex unit of an image forming apparatus in which recording paper with single-sided printing is stored and aligned in an intermediate tray, and paper is fed again in order to print on the back side of the recording paper. a first conveyance path for refeeding recording paper that has been printed on one side; and a second conveyance path for ejecting the paper to another unit without refeeding; The present invention provides a double-sided unit for an image forming apparatus, which includes a switching means for switching between the conveyance path and the second conveyance path.

[Function] In the duplex unit of the image forming apparatus according to the present invention, during normal duplex printing, the switching means is set to the first conveyance path side to refeed the paper, and when a jam occurs, the switching means is switched on. is switched to the second conveyance path side, so that the recording paper is ejected to another unit without being re-fed.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail using the drawings.

FIG. 2 shows the overall configuration of a laser printer system equipped with a duplex unit according to an embodiment of the present invention.

In the figure, the laser printer system includes a paper feed cassette 202 that stores recording paper, an optical system 203 that emits a laser beam corresponding to image information, and a surface of the paper that is image-exposed by the laser beam from the optical system 203. A photosensitive drum 204 that forms an electrostatic latent image corresponding to image information on
, a developer 250 that develops the electrostatic latent image formed on the surface of the photoreceptor drum with toner, and a paper feed cassette 2.
A registration roller 205 conveys the recording paper fed from 02 to a transfer section at a predetermined timing, and transfers the visualized image on the photoreceptor drum 204 to the conveyed recording paper, and A printer main body 201 consisting of a transfer/separation charger 206 that separates the recording paper after transfer from the photoreceptor drum 204 and a fixing device 207 that fixes the image transferred to the recording paper, and a switching roller 209
, a reversing unit 208 having a reversing path 210 and a recording paper tray 211, a duplex unit 100 that refeeds paper during double-sided printing, a sorter 212 that stores ejected recording paper, and a large-volume paper feed section 213. It is composed of a discharged sheet storage section 214 that stores the jammed recording paper.

In the above configuration, the recording paper fed from the paper feed cassette 202 is conveyed to the transfer unit via the registration rollers 205 at a constant timing. On the other hand, an electrostatic latent image corresponding to image information is formed by a laser beam on the surface of the photoreceptor drum 204, which has been uniformly charged in advance, and the electrostatic latent image is visualized by a developing device 250. Thereafter, the image on the photosensitive drum 204 is transferred by a transfer/separation charger 206 to the recording paper that has been conveyed to the transfer section. After the transfer, the recording paper is separated from the photosensitive drum 204 by a transfer/separation charger 206, and then fixed by a fixing device 207 to complete printing.

In the case of single-sided printing, the recording paper after printing is discharged to the sorter 212 or the recording paper tray 211 by the switching roller 209.

In the case of double-sided printing, the single-sided printed recording paper is reversed in the reversing path 210 of the reversing unit 208 and then conveyed into the double-sided unit 100. Double-sided unit 1
The recording paper conveyed to 00 is again fed to the printer main body 201, printing is performed on the back side, and after printing on both sides is completed, it is fed to the printer main body 201 and then transferred to the sorter 212 or the recording paper tray 21.
1 muko is discharged.

The detailed configuration of the duplex unit 100 according to this embodiment is explained in the first section.
The explanation will be given based on the figure and FIGS. 3 and 4.

The duplex unit 100 includes a take-in roller 101 that takes in the recording paper conveyed from the reversing unit 208, and a discharge gate 102 that selects the discharge position of the recording paper depending on the paper size.
Intermediate tray 10 that accommodates recording paper for double-sided printing
3. Jogger unit 1 that regulates the horizontal direction of recording paper
04, a shifting roller 105, a stopper 106 that temporarily stops conveyance of the recording paper on the intermediate tray 103, and a feed roller 108
, has an intermediate roller 109 and a ball discharge roller 110,
A paper refeeding unit 107 that feeds paper to the print main body 201, a lower discharge roller 111 that discharges recording paper to a paper discharge storage unit 214 in the event of a jam, a switching unit 112 that switches the conveyance direction of the recording paper, and an entrance 113. .114 and exit 115
．． 116.

Here, the path from the take-in roller 102 to the paper re-feed unit 108 forms a conveyance path for re-feeding recording paper that has been printed on one side, and the path from the take-in roller 102 to the lower discharge roller 111 forms a conveyance path after a jam occurs. It forms a conveyance path for discharging the recording paper.

The switching means 112 is for selectively switching and feeding the recording paper to the paper refeeding section 107 side or the lower discharge roller 111 side, and as shown in FIGS.
01 and an inlet gate solenoid 302 that switches the inclination direction of the switching pawl 301.

When the population gate solenoid 302 is in the OFF state, the tip of the switching pawl 301 is tilted to the left, and the recording paper taken in by the take-in roller 101 flows to the right by the switching pawl 301, as shown in FIG. It is regulated as follows.

That is, the recording paper is sent to the paper refeeding section 107 side. On the other hand, when the inlet gate solenoid 302 is in the ON state, the tip of the switching pawl 301 is tilted to the right, and the intake roller 1
The recording paper taken in by 01 is transferred to the switching claw 3 as shown in Fig. 4.
01, the flow is regulated to the left, and the lower discharge roller 1
Sent to the 11th side.

In addition, in the vicinity of the population 113, an inversion unit 208
An entrance sensor 303 is provided for detecting the presence or absence of a single-sided printed recording sheet that has been reversed and conveyed.

FIG. 5 shows the operation timing of the population gate solenoid 302 and the large mouth sensor 303. As you can see from the figure,
The entrance sensor 303 is turned ON every time a recording paper passes through the entrance 113 to detect the presence of recording paper, and the entrance gate solenoid 302 is selectively set to OFF or ON.

Next, the operation of the duplex unit 100 configured as described above will be explained.

After printing in the printer main body 201, the reversing unit 2
The duplex unit 100 is reversed on the reversing path 210 of 08.
The single-sided printed paper transported to is taken in by the take-in roller 101 via the entrance 113. In the case of double-sided printing, since the entrance gate solenoid 302 is in the OFF state, the recording paper is sent in the direction of discharge date 1-102 by the switching pawl 301 of the switching means 112.

At the discharge gate 102, the discharge position of the recording paper is selected depending on the paper size, and the recording paper is stored in the intermediate tray 103. The recording paper accommodated in the intermediate tray 103 is conveyed by a shifting roller 105 to a position where it reaches a stopper 1064, and then laterally regulated by a jogger unit 104 to align its axes.

When the stopper 106 is released, the recording paper that has been regulated in the lateral direction is conveyed in the order of the feed roller 108 of the paper refeeding section 107, the intermediate roller 109, and the ball discharging roller 110.
The paper is again fed to the printer main body 201 from the outlet 115.

Note that when paper is fed from the mass paper feed section 213, the recording paper fed from the mass paper supply section 213 through the inlet 114 is transferred to the intermediate roller 109 of the paper refeed section 107 and the ball discharging roller 11.
0 and feeds the paper from the outlet 115.

Here, consider a case where a jam occurs while the recording paper is being continuously conveyed in double-sided printing.

In this case, when the jam occurs, the double-sided unit) 1
When there is no recording paper near the entrance sensor 303 of 00, and when the recording paper is ONL with the entrance sensor 303, and
It is assumed that the switching claw 301 is set to the paper refeeding unit 107 side (the entrance gate solenoid 302 is in the OFF state).

If a jam occurs, all the recording paper downstream of the paper that caused the jam will be ejected.
The amount of recording paper remaining on the conveyance path is reduced, and the work of removing the recording paper becomes easier.

Therefore, in the duplex unit 100 of this embodiment, if there is no recording paper near the inlet sensor 303 when a jam occurs, the inlet gate solenoid 302 is immediately turned ONL to switch the switching claw 301 as shown in FIG. is set to the state shown in FIG. 4, and then all the recording paper conveyed from the inlet 123 is sent to the normal discharge roller 111 side. The recording paper sent to the main discharge roller 1]1 is discharged from the outlet 116 to the discharge paper storage section 214 in the state of single-sided printing.

At the time the jam was ordered, the recording paper was present and the entrance sensor 3
03 is ON, and the switching claw 301 is set to the paper refeed section 1.
If it is set to the 07 side, the take-in roller 101
When the recording paper being conveyed to the intermediate tray 103 side leaves the entrance sensor 303 and the population sensor 303 is turned off, the entrance gate solenoid 302 is turned on and the switching claw 30 is turned on.
1 is in the state shown in FIG. In this case as well, then the entrance 1
All the recording paper conveyed from 13 is transferred to the normal ejection roller 1.
11, the paper is discharged to the discharge paper storage section 214.

By performing the above-described operation when a jam occurs, less recording paper remains on the conveyance path of the apparatus when a jam occurs, and the recording paper removal process becomes easier. In addition, by counting the number of times the inlet sensor 303 detects recording paper after a jam occurs, and using that count value as data on the number of sheets output after a jam occurs, it is possible to manage the page when starting printing again after the recording paper removal process. becomes easier.

〔Effect of the invention〕

As described above, according to the duplex unit of the image forming apparatus of the present invention, there is a first conveyance path for refeeding the recording paper that has been printed on one side, and a first conveyance path for refeeding the recording paper that has been printed on one side, and for ejecting the paper to another unit without refeeding. and a switching means for switching between the 10th) transport path and the second transport path to switch the transport path when a jam occurs and transfer the single-sided printed recording paper to another Therefore, when a jam occurs, less recording paper remains on the conveyance path within the apparatus, and the recording paper removal work can be simplified.

[Brief explanation of drawings]

FIG. 1 is a sectional view schematically showing a duplex unit according to an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the overall configuration of a laser printer device equipped with a duplex unit according to the present invention, and FIGS. 3 and 4 5 are enlarged views of essential parts showing the switching operation of the conveyance direction by the duplex unit of this embodiment, and FIG. 5 is a timing chart showing the operation of the entrance sensor and the entrance gate solenoid of the duplex unit. Explanation of symbols 100--Double-sided unit 103-Intermediate tray 107
- Paper refeed section 112 - Switching means 201 - Printer body 20B - Reversing unit 214 - Discharged paper storage section 3
01-Switching claw 302-Population gate solenoid 303...Entrance sensor

Claims (1)

[Scope of Claims] In a duplex unit of an image forming apparatus, in which recording sheets with single-sided printing are stored and arranged in an intermediate tray, and paper is fed again to print on the back side of the recording sheets, the recording sheets with single-sided printing are arranged. 1st for refeeding paper
a conveyance path, and a second conveyance path for discharging the paper to another unit without refeeding, and the first conveyance path and the second conveyance path are provided.
1. A duplex unit for an image forming apparatus, comprising: switching means for switching a conveyance path.