JP4117014B2 - Paper transport mechanism and duplex printing apparatus using the same - Google Patents

Description

  The present invention relates to a paper transport mechanism applicable to an image forming apparatus represented by a copying machine, a printer, and the like. The present invention also relates to a double-sided printing apparatus using this paper transport mechanism.

  In an image forming apparatus typified by a copying machine or a printer, paper conveyance paths are formed in various places. For example, in many cases, a paper supply device for stacking and storing paper is provided inside and below the image forming apparatus main body. In order to supply paper to a transfer unit provided inside the main body, The sheet conveyance path is vertically formed along the side surface of the main body. In addition, when the image forming apparatus is provided with a double-sided printing device, the paper conveyance path is substantially omitted at the bottom of the double-sided printing device provided between the transfer unit and the paper feeding device, that is, at the ceiling of the space for housing the paper feeding device. Often shaped horizontally.

The double-sided printing apparatus makes it possible to print the other side of a sheet of which one side is printed and pulled out of the fixing unit by a roller to reversely rotate the roller and switch the paper transport direction. The paper transport path is used to send the paper whose transport direction has been switched in this way to the transfer unit again. An example of a double-sided printing apparatus provided with such a paper conveyance path can be seen in Japanese Patent Application Laid-Open No. 2004-133620.
JP 2001-183954 A

  As described above, the double-sided printing device of the image forming apparatus is often provided above the paper supply device, and even if the exterior cover of the main body of the image forming apparatus is opened, the paper conveyance path of the double-sided printing device is greatly exposed. I can't. Therefore, when a paper jam occurs in this paper conveyance path, it is necessary to put a hand in a narrow place, and the paper causing the jam may not be removed well or the paper may not reach the paper. When the paper is torn out forcibly, a piece of paper remains in the transport path, and adversely affects the next paper to be fed, causing image defects and transport defects. In this regard, Patent Document 1 takes the following measures.

  In the image forming apparatus described in Patent Document 1, the double-sided printing unit is unitized so that it can be pulled out from the main body. If a paper jam occurs in the paper conveyance path of the double-sided printing unit, the double-sided printing unit is installed. Pull out from the main body to jam. As a result, the sheet conveyance path is completely exposed to the outside of the image forming apparatus, so that it is possible to perform jam processing very easily and reliably. However, there are models in which the duplex printing unit is fixed to the main body of the image forming apparatus in a model that further saves space and costs. In such a model, it is not possible to adopt a jam processing method in which the double-sided printing unit is pulled out from the main body.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and is capable of easily performing paper jam processing even when the paper conveyance path is not completely exposed to the outside of a device equipped with the paper conveyance path. The purpose is to provide a mechanism. It is another object of the present invention to provide a high-performance duplex printing apparatus using such a paper transport mechanism.

In order to solve the above problems, a paper transport mechanism according to the present invention includes a first transport guide disposed substantially horizontally on a paper transport path, and a sheet connected to the first transport guide downstream of the paper transport path. And changing the posture of at least the first conveyance guide among the second conveyance guide disposed substantially horizontally on the conveyance path and the first conveyance guide and the second conveyance guide from the substantially horizontal posture to an inclined posture. A tilting mechanism that enables, a paper storage unit that is disposed at a position that interferes at least when the first transport guide is in the tilted posture, and that stores paper to be supplied to the paper transport path; and the paper storage unit of, it is seen including a drawer mechanism, a to allow withdrawal of the downstream direction of the paper transport path of the first conveying guide and the second conveying guide is contiguous, the tilt mechanism, the first transport gas And at least the first conveyance guide is inclined downward with respect to the edge of the second conveyance guide and the second conveyance guide as a turning point, and at least the first conveyance guide of the first conveyance guide. A pull-down knob is provided at an end edge opposite to the side where the guide and the second conveyance guide are connected (Claim 1).

  The said structure WHEREIN: It is desirable for the said 1st conveyance guide and the 2nd conveyance guide to consist of a flat member (Claim 2).

Furthermore, in the present invention, the above-mentioned paper transport mechanism is provided in the double-sided printing apparatus (claim 3) .

  According to the configuration of the present invention, the first conveyance guide and / or the second conveyance guide is positioned by the tilting mechanism regardless of the position of the first conveyance guide and the second conveyance guide. You can easily remove the jammed paper by changing it and reaching for it. Therefore, even when the paper conveyance path is not completely exposed to the outside of the device equipped with the paper conveyance path, paper jam processing can be easily performed.

  Furthermore, in the present invention, since the above-mentioned paper transport mechanism is provided in the double-sided printing apparatus, for example, even if the double-sided printing apparatus is fixed to the image forming apparatus and cannot be pulled out, paper jam processing can be easily performed. Can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. Here, a printer is given as an example of an image forming apparatus to which the paper transport mechanism is applied, and the paper transport mechanism of the present invention is used in a double-sided printing apparatus mounted on the printer.

  FIG. 1 is a schematic perspective view of the paper transport mechanism as viewed from below. 2A and 2B are schematic vertical sectional views showing a paper guide state and a jam processing state of the paper transport mechanism. FIG. 2A shows a paper guide state, and FIG. 2B shows a jam process on the upstream side in the paper transport direction. FIG. 2C shows a state in which jam processing is performed on the downstream side in the paper conveyance direction. 3 is a schematic perspective view of the paper transport mechanism and the paper cassette as viewed from above, and FIG. 4 is a schematic vertical sectional view showing the schematic structure of the printer.

  First, the outline of the structure of a printer to which the paper transport mechanism of the present invention is applied will be described with reference to FIG.

  A paper cassette 10 serving as a paper supply unit is disposed below the inside of the main body 2 of the printer 1. The paper cassette 10 can be extracted from the main body 2 in the horizontal direction (the arrow direction in FIG. 4), and the paper P is stacked and accommodated therein. The paper P is sent out toward the upper right of the paper cassette 10 in FIG. Subsequently, a registration roller 3, an image forming unit 4, a transfer unit 5, a fixing unit 6, a branching unit 7, and a sheet discharging unit 8 are disposed downstream of the sheet conveyance direction. The paper discharge unit 8 is provided on the upper surface of the main body 2.

  A double-sided printing device 20 is disposed above the paper cassette 10 and below the transfer unit 5. A sheet transport mechanism 30 is provided below the duplex printing apparatus 20. The paper transport mechanism 30 constitutes one surface below the paper transport path 21 in the duplex printing apparatus 20. When performing double-sided printing, the conveyance direction of the paper P that has passed through the branching section 7 is switched and sent to the double-sided printing apparatus 20, and the paper passes through the paper conveyance path 21 to the transfer section 5 again via the registration rollers 3. P is conveyed.

  Next, a detailed configuration of the paper transport mechanism according to the embodiment of the present invention will be described with reference to FIGS. As described above, the paper transport mechanism 30 of the present invention is used in the lower portion of the duplex printing apparatus 20 and is used to send the paper P whose transport direction has been switched to the transfer unit 5 again.

  In the paper transport mechanism 30, the upstream paper guide member 31 (first transport guide) is upstream on the upstream side in the paper transport direction, and the downstream paper guide member 32 (second transport guide) is substantially horizontal on the downstream side. Is provided. These two members are hingedly connected by a connecting portion 33 (a part of the tilting mechanism), and are attached to the duplex printing apparatus 20. The connecting portion 33 is provided with a torsion coil spring 34 (a part of the tilting mechanism), and the upstream side paper guide member 31 and the downstream side paper guide member 32 are always urged to a substantially horizontal paper guide state. An angle determining mechanism (not shown) is provided between the upstream paper guide member 31 and the downstream paper guide member 32, and the rotation by the torsion coil spring 34 is stopped at the angle shown in FIG. . As is apparent from FIGS. 1 to 3, the upstream side paper guide member 31 and the downstream side paper guide member 32 are formed of flat members.

  From the state of FIG. 2A, the upstream side paper guide member 31 can lower the upstream side portion in the paper transport direction with the connecting portion 33 as a fulcrum by pulling down the knob 35 (see FIG. 2B). . Further, the downstream side paper guide member 32 can lower the downstream side portion in the paper transport direction with the connecting portion 33 as a fulcrum by pulling down the knob 36 (see FIG. 2C). When a paper jam occurs in the duplex printing apparatus 20, a hand is put in the space after the paper cassette 10 is removed, and the upstream paper guide member 31 or the downstream paper guide member 32 is lowered to perform the jam processing. be able to. As described above, since these two paper guide members are biased by the torsion coil spring 34, when they are released from the knobs 35 and 36, they automatically return to the substantially horizontal paper guide state.

  A rotatable guide roller 38 is provided on the lower side upstream of the connection portion 37 of the upstream sheet guide member 31 in the sheet conveyance direction. The guide rollers 38 are formed of an elastic material such as synthetic rubber or elastomer, and are provided on both the left and right sides with respect to the paper transport direction. When the paper cassette 10 is inserted, the upstream paper guide member 31 is supported from below in such a shape that a guide roller 38 rides on the upper surface 11a of the side plate 11 which is a support surface provided in the paper cassette 10. (See FIG. 3). Thereby, even if the resilience of the torsion coil spring 34 is lowered, the upstream side paper guide member 31 can be held in the paper guide state, and the paper transport mechanism 30 is configured correctly.

  A roller support member 40 is provided below the upstream sheet guide member 31 and the downstream sheet guide member 32. The roller support member 40 is provided with a paper transport roller 41 that protrudes upward by a predetermined amount from an opening 31a provided in the upstream paper guide member 31 at a substantially central portion in the paper transport direction (see FIG. 3). ). The paper transport roller 41 forms a nip that contacts the paper transport roller 22 provided in the double-sided printing apparatus 20 and allows the paper to pass therethrough.

  The upstream end of the roller support member 40 in the sheet conveyance direction is rotatably supported by the connection portion 37 of the upstream sheet guide member 31. The connecting portion 37 is provided with a torsion coil spring 42 which is an urging means for urging the roller support member 40 in the direction of the sheet guide member. Further, a contact protrusion 43 that contacts the lower surface of the downstream sheet guide member 32 is provided at the downstream end of the roller support member 40 in the sheet conveyance direction.

  With the above configuration, when the upstream side of the upstream paper guide member 31 is lowered in the paper conveyance direction, the contact protrusion 43 of the roller support member 40 contacts the lower surface of the downstream side paper guide member 32, and the connecting portion 37 is a fulcrum. As shown in FIG. 2B, the roller support member 40 is lowered so that the contact protrusion 43 slides. Similarly, when lowering the downstream side of the downstream paper guide member 32 in the paper conveyance direction, the contact protrusion 43 contacts the lower surface of the downstream paper guide member 32, and the contact protrusion 43 serves as a fulcrum with the connection portion 37 as a fulcrum. The roller support member 40 is lowered so as to slide (see FIG. 2C).

  Therefore, at the same time when either the upstream sheet conveyance guide 31 or the downstream sheet conveyance guide 32 is lowered, the sheet conveyance roller 41 of the roller support member 40 is lowered and the sheet conveyance roller of the duplex printing apparatus 20 is automatically lowered. 22 can be separated. As a result, the paper P that is being transported through the nip formed by the paper transport rollers 22 and 41 can be easily taken out.

  Thus, when either the upstream side paper guide member 31 or the downstream side paper guide member 32 is lowered, the presence of the roller support member 40 does not hinder the movement, and the paper guide member is smoothly lowered. Can be made. Further, by providing the torsion coil spring 42 at the connecting portion 37 of the roller support member 40, the paper transport roller 41 always protrudes a predetermined amount on the upper surface, which is the paper transport surface of the upstream paper guide member 31, in the paper guide state. Therefore, it is possible to further improve the paper conveyance performance.

  Further, according to the above configuration, even when a paper jam occurs in any of the upstream paper guide member 31 and the downstream paper guide member 32, these paper guide members are lowered and handed there. It is possible to easily remove the jammed paper P by extending the length. Therefore, even if the paper transport mechanism 30 is not completely exposed to the outside of the printer 1 as in this embodiment, it is possible to easily perform paper jam processing.

  Further, since the paper transport mechanism 30 is provided in the double-sided printing apparatus 20, even if the double-sided printing apparatus 20 is fixed to the printer 1 and cannot be pulled out as in this embodiment, the paper can be easily printed. A high-performance double-sided printing apparatus 20 capable of performing jam processing can be obtained.

  Although the embodiment of the present invention has been described above, various modifications can be made without departing from the spirit of the present invention.

  In the above embodiment, the paper transport mechanism of the present invention is applied to the double-sided printing apparatus of the printer. Is possible.

  According to the configuration of the present invention, even when a paper jam occurs at either the upstream side or the downstream side of the paper guide member, the paper guide member is lowered and the jam is easily achieved by reaching out there. The paper that caused the error can be removed. Therefore, it is possible to obtain a high-performance paper transport mechanism that can easily perform paper jam processing even if the paper transport path is not completely exposed to the outside of the device including the paper transport path.

It is the schematic perspective view which looked at the paper conveyance mechanism which concerns on embodiment of this invention from the downward direction. FIG. 2 is a schematic vertical sectional view showing a paper guide state and a jam processing state of the paper transport mechanism shown in FIG. 1. FIG. 2 is a schematic perspective view of the paper transport mechanism and the paper cassette shown in FIG. 1 as viewed from above. It is a model vertical sectional view showing a schematic structure of a conventional printer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer 2 Main body 10 Paper cassette 11a Side board upper surface 20 Duplex printing part 21 Paper conveyance path 22 Paper conveyance roller 30 Paper conveyance mechanism 31 Upstream paper conveyance guide (1st conveyance guide)
31a Opening 32 Downstream side paper conveyance guide (second conveyance guide)
33 Connecting portion 34 Torsion coil springs 35 and 36 Knob 37 Connection portion 38 Guide roller 40 Roller support member 41 Paper transport roller 42 Torsion coil spring 43 Abutting protrusion

Claims (3)

A first conveyance guide disposed substantially horizontally on the sheet conveyance path;
A second transport guide disposed substantially horizontally in the paper transport path so as to be continuous with the first transport guide downstream of the paper transport path;
An inclination mechanism that enables at least the first conveyance guide of the first conveyance guide and the second conveyance guide to be changed in posture from the substantially horizontal posture to an inclined posture;
A paper storage section that is disposed at a position that interferes when at least the first transport guide is in the inclined posture, and that stores paper to be supplied to the paper transport path;
It said sheet storing section, viewed contains a drawer mechanism, a to allow withdrawal of the downstream direction of the paper transport path of the first conveying guide and the second conveying guide is contiguous,
The tilt mechanism is configured to incline at least the first transport guide downward with an end edge of the first transport guide and the second transport guide on the continuous side as a turning point.
A pull-down knob is provided at least on an edge portion of the first conveyance guide opposite to the side where the first conveyance guide and the second conveyance guide are connected. A paper transport mechanism.   The paper transport mechanism according to claim 1, wherein the first transport guide and the second transport guide are formed of flat plate members. A double-sided printing apparatus using the paper transport mechanism according to claim 1 .

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