JP2002241017A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device for efficiently carrying paper, and capable of instantly informing residual paper in a double side reversing unit by improving the double side reversing unit. SOLUTION: The double side reversing unit 2 has two reversing passages of a first reversing passage 9 and a second reversing passage 10, and introduces the second paper to the second reversing passage by switching of a switching claw 7 after introducing the first paper to the first reversing passage 9. A paper carry to a refeeding passage 13 by reverse rotation of a reversing roller 8 is performed in order of paper introduced to the second reversing passage, and paper successively introduced to the first reversing passage. Such constitution can reduce reciprocal switching of rotation of a motor conventionally performed with every one sheet of paper with every two sheets of paper, and can reduce time required for a print and a load to the device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus having a double-sided printing function, and more particularly, to an image forming apparatus with improved sheet conveyance of a double-sided reversing unit.

[0002]

2. Description of the Related Art An image forming apparatus having a two-sided printing function includes a two-sided reversing unit of a different system from a sheet transport path for forming an original image. Is received, reversed, and then re-fed to the image forming unit, thereby performing double-sided printing. Accordingly, the paper transport path is different between single-sided printing and double-sided printing. Naturally, there is a problem that extra time is required for double-sided printing due to the transport path of the double-sided reversing unit.

[0003] In addition, since a configuration for reversing the paper is required at the time of double-sided printing, the transport path in the double-sided reversing unit is complicated, and there is a high possibility that a jam occurs in the double-sided reversing unit. Each time the jam occurs, the apparatus is stopped, which causes trouble in operation.

Further, if the power is turned off while the paper remains in the duplex reversing unit, the remaining paper in the unit causes a trouble in the duplex printing operation at the next power-on. Regardless of whether or not there is any remaining paper in the unit, jam detection in the double-sided reversing unit was performed when the power was turned on. However, this operation performed irrespective of the presence or absence of the remaining paper has a problem that there is a loss in power consumption and time.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention has improved a duplex reversing unit so that paper can be transported efficiently, and the notification of remaining paper in the duplex reversing unit is immediately sent. It is an object to provide an image forming apparatus that can perform the image forming apparatus.

[0006]

According to an aspect of the present invention, there is provided an image forming unit for forming an image on a sheet sent from a sheet feeding unit, and an image forming unit. And a double-sided reversing unit for receiving the sheet printed on one side and reversing the sheet, and re-feeding the sheet to the image forming unit. Equipment. According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the image forming apparatus can be used in only one of the two inversion paths. According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, when a sheet remains in at least one of the two reversing paths, the information is transmitted. An image forming apparatus having an informing means for informing.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of a printer having a duplex printing function according to an embodiment of the present invention. In the image forming unit of the printer main body 1, the paper on which one side is printed passes through a paper conveyance path in the main body 1 and is conveyed to the duplex reversing unit 2. The sheet is reversed by advancing according to a paper transport path provided in the duplexing unit 2, and is again transported from the duplexing unit 2 outlet to the main body 1 having the image forming unit. The image is formed, and the sheet is discharged outside the main body 1 in a state where both sides are printed.

FIG. 2 is a detailed view of the duplex reversing unit. The duplex reversing unit 2 includes an entrance hole 3 serving as an entrance when a sheet is fed from the main body 1, an entrance sensor 4 for detecting a sheet at the entrance, a path switching claw 5, a reversing sensor 6, A switching claw 7 for selecting one of the reversing paths according to the situation;
And two inversion paths through which the sheet passes, namely a first inversion path 9 and a second inversion path 10, and sheet detection sensors 11 and 12 for detecting whether or not there is a sheet in each of the inversion paths.
A re-feeding path 13 through which the paper passes when returning to the main body 1 again, a transport roller 14 for transporting the paper, an exit roller 15, an exit sensor 16 for detecting the paper at the exit, 1 has a sheet re-feeding port 17 which serves as an exit of the double-sided reversing unit when the sheet is conveyed again.

Next, the procedure of processing a sheet in the duplex reversing unit will be described. FIG. 3 is a flowchart illustrating a procedure of processing a sheet in the duplex reversing unit. First, when the first sheet of paper is fed from the entrance hole 3, the entrance sensor 4
N, and the course switching claw 5 is moved OP
The state becomes EN. When the sheet is conveyed along the path, the reversing sensor 6 is turned on, and at the same time, based on the information of the sheet detecting sensors 11 and 12 provided in the respective reversing paths, the reversing path side where the switching claw 7 is open is provided. OPEN to However, when both are empty, the first inversion path 9 is selected as an initial state. And the first sheet is the first
Proceed to the reversing path 9 and when the reversing sensor 6 is turned off,
Move the inversion path switching claw 7 toward the second inversion path 10
Then, the second sheet is transported to the second reverse path 10. When the conveyance to the second reversing path 10 is completed, the motor is rotated reversely, and at the same time, the path switching claw 5 is opened to the re-feeding path 13 side. The reversing roller 8 rotates in reverse in response to the motor, and conveys the sheet conveyed to the second reversing path 10 from the second reversing path 10 along the re-feeding path 13 in order to re-feed the sheet to the main body. Next, the conveyance proceeds, and the reversal sensor 6
Is turned OFF, the switching claw 7 is opened toward the first reversing path 9 and the sheet is conveyed along the re-feeding path 13 following the previous sheet. When the conveyance progresses and the reversing sensor 6 is turned off, the path switching claw 5 is opened to the reversing path side. The above is a series of operations, and thereafter, this operation is repeated.

Conventionally, sheet reversing work has been performed by reversing the rotation of the motor for each sheet of paper.
By providing two, the switching of the rotation direction of the motor is 2
Since only one sheet is required, the time required for printing and the load on the apparatus are reduced, and the efficiency of sheet transport in the double-sided reversing unit can be increased.

Next, an operation example when a paper jam occurs in at least one of the reversing paths will be described. FIG. 4 is a flowchart illustrating a processing procedure when at least one of the reversing paths causes a paper jam. When a paper jam occurs in the reversing path, it is determined whether the reversing path is either one or both (a), and if it is one (b), paper conveyance is continued using another reversing path. If both are (c), the paper conveyance is stopped at that point. That is, even if a paper jam occurs in one of the two reversing paths, only the remaining reversing path is used.
Printing efficiency can be increased by continuing the paper transport operation. In addition, since it is not necessary to stop the machine and carry out the jam processing each time, time loss in operation can be reduced.

When one of the reversing paths stops conveying due to a paper jam and continues to convey only on the other reversing path, the information is provided by a notifying means provided in the printer body 1. Notify. With such a configuration, the state of the printer 1 can be immediately confirmed. Further, when there is a remaining sheet in one of the reversing paths at the time when the continuous print job is completed, the information is notified, and the information can be removed without fail. By using two reversing paths, paper can be transported efficiently.

[0013]

As described above, by providing two paper reversing paths in the double-side reversing unit, the time required for the rotation switching operation of the reversing roller can be reduced, and the paper transport speed can be increased. An image forming apparatus can be provided. In addition, even if a paper jam occurs in either one of the reverse paths in the double-sided reverse unit, control is performed so that only the other reverse path is used, and the paper transport operation is continued, thereby increasing print efficiency. Image forming apparatus can be provided. Further, when the sheet is conveyed by only one of the reversing paths, the information is obtained by the notifying means, so that the state of the printer can be immediately confirmed. An image forming apparatus capable of performing the above can be provided.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a printer having a two-sided printing function.

FIG. 2 is a detailed view of a duplex reversing unit.

FIG. 3 is a flowchart illustrating a procedure of processing a sheet in a duplex reversing unit.

FIG. 4 is a flowchart illustrating a processing procedure when a paper jam occurs in at least one of the reverse paths.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 printer 2 double-sided reversing unit 3 entrance hole 4 entrance sensor 5 path switching claw 6 reversing sensor 7 switching claw 8 reversing roller 9 first reversing path 10 second reversing path 11 first sheet detection sensor 12 second sheet detection sensor 13 resupply Paper path 14 Conveying roller 15 Exit roller 16 Exit sensor 17 Refeed port

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 15/00 106 G03G 15/00 106 526 526 F Term (Reference) 2H028 BA06 BA09 BB04 BD01 2H072 AA02 AA16 AA22 AA32 CB01 CB03 EA02 JA02 JA04 3F048 AA03 AA05 AB01 BA05 BA14 BB02 BC03 CC01 DA06 EB22 3F053 BA03 BA12 BA14 BA29 EA03 EA05 EB01 EB04 EC02 EC06 ED25 3F100 AA02 BA24 CA03 CA12 CA15 CA17 DA01 EA02 EA13

Claims (3)

[Claims] An image forming section for forming an image on a sheet sent from a sheet feeding section; a sheet printed on one side by the image forming section is received, reversed, and re-supplied to the image forming section; An image forming apparatus having a two-sided printing function having a two-sided reversing unit for forming a sheet, the image forming apparatus having two sheet reversing paths. 2. The image forming apparatus according to claim 1, wherein only one of the two inversion paths can be used. 3. The image forming apparatus according to claim 1, further comprising a notifying unit for notifying, when a sheet remains in at least one of the two reversing paths, information on the remaining sheet. An image forming apparatus comprising: