JP2005029313A - Perfecting printing press - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a perfecting printing press capable of obtaining stable paper conveying property while the paper is certainly directed to a paper delivery passage direction. <P>SOLUTION: The perfecting printing press 1 is provided with an intermediate tray 2 for once storing the paper having one printed surface; a paper intrusion passage 3 to the intermediate tray 2; and the paper delivery passage 4. A driving roller 5 and a driven roller 6 are provided at an entrance of the intermediate tray 2. The driven roller 6 is abutted on the driving roller 5 from above and an offset amount D with the driving roller 6 is set such that a tip end of the paper delivered from the intermediate tray 2 is directed to the paper delivery passage 4. Thereby, since the paper delivered from the intermediate tray 2 is correctly conveyed toward the paper delivery passage 4 without being directed to the paper intrusion passage 3, jamming of the paper is not generated at the entrance of the paper delivery passage 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a double-sided printing apparatus used in an image forming apparatus typified by a copying machine or a printer.
[0002]
[Prior art]
Some image forming apparatuses represented by copying machines, printers, and the like can print on both sides of a sheet with a single operation. In such an image forming apparatus, after printing one side of a sheet, the sheet is caused to enter the temporary storage unit by a roller, and the roller is rotated in reverse to switch the conveyance direction of the sheet and to be discharged from the temporary storage unit. Thus, a double-sided printing device is provided that enables printing on the other side.
[0003]
An example of such a conventional double-sided printing apparatus is shown in FIGS. FIG. 6 is a schematic cross-sectional view showing a schematic structure of a paper conveyance direction switching unit of a conventional double-sided printing apparatus, and shows a state when paper is fed into an intermediate tray that is a temporary storage unit of the double-sided printing apparatus; FIG. 7 is a schematic cross-sectional view showing a state when the sheet is discharged from the intermediate tray.
[0004]
6 and 7, the right side of the duplex printing apparatus 1 is provided with an intermediate tray 2 that is a temporary storage unit that temporarily stores the paper on which one side is printed. On the upper left side of the intermediate tray 2, there is provided a paper entry path 3 through which the paper on which one side is printed is sent to the intermediate tray 2. On the left side of the intermediate tray 2, a paper discharge path 4 is provided at an adjacent position below the paper entry path 3.
[0005]
A driving roller 5 and a driven roller 6 are provided at the entrance of the intermediate tray 2. The drive roller 5 is rotated by a motor (not shown), and switches the paper transport direction by switching the rotation direction. The driven roller 6 contacts the drive roller 5 from above and rotates according to the rotation of the drive roller 5.
[0006]
A solenoid 7 is provided above the driven roller 6. The plunger 7 a of the solenoid 7 is connected to the shaft 6 a of the driven roller 6 by a link 8. The shaft 6 a of the driven roller 6 is housed in a roller guide 9 a provided on the support member 9. The support member 9 is a plate-like member, and the roller guide 9 a provided on the support member 9 is a groove cut perpendicular to the intermediate tray 2.
[0007]
6 and 7, the driven roller 6 is moved vertically up and down with respect to the intermediate tray 2 along the roller guide 9a as the plunger 7a moves left and right. The driven roller 6 moves away from the driving roller 5 (see FIG. 6) by moving upward, and abuts by moving downward (see FIG. 7). The driven roller 6 is separated from the driving roller 5 only when a sheet enters the intermediate tray 2.
[0008]
Subsequently, the operation of the double-sided printing apparatus 1 will be described. When the paper on which one side is printed is sent to the intermediate tray 2 through the paper entrance path 3, the driven roller 6 is moved upward by the solenoid 7 so that the driven roller 6 does not get in the way. Separate (see FIG. 6). Thereafter, the drive roller 5 is rotated clockwise to convey the sheet to the intermediate tray 2. When the paper is stored in the intermediate tray 2, the driven roller 6 is moved downward to come into contact with the driving roller 5 (see FIG. 7) to form a nip through which the paper is inserted to counteract the rotation of the driving roller 5. Switch clockwise. The drive roller 5 and the driven roller 6 discharge the sheet toward the sheet discharge path 4.
[0009]
Here, the state when the sheet is discharged from the intermediate tray 2 will be described with reference to FIG. FIG. 8 is a schematic cross-sectional view of a principal part showing a detailed paper state when the paper is discharged from the intermediate tray 2. In FIG. 8, when the paper P curled upward in the paper entry path 3 direction is conveyed to the intermediate tray 2, the paper P is curled upward when the paper P is discharged from the intermediate tray 2. For this reason, the sheet cannot be conveyed to the paper discharge path 4 side, and a paper jam may occur at the entrance of the paper discharge path 4. This takes time and effort for jamming, and wastes time with the paper. In addition, when the paper is damaged, a small piece of paper remains in the apparatus, thereby causing problems such as deterioration in image forming performance of the apparatus and malfunction of the apparatus.
[0010]
Patent Documents 1 and 2 show examples of techniques proposed as countermeasures against paper curling that contributes to paper jam occurring in such a duplex printing apparatus.
[0011]
[Patent Document 1]
JP 2000-26006 A [Patent Document 2]
Japanese Patent Laid-Open No. 2000-26007
[Problems to be solved by the invention]
In the image forming apparatus described in Patent Document 1, in a pair of conveying rollers provided immediately before the sheet reaches the double-sided printing apparatus, one of the rollers is swung around the axis of the other roller by a predetermined angle to correct the curl of the sheet. A technique to make it has been proposed. In such a method, even if the paper curl is eliminated when the paper enters the double-sided printing apparatus, when the paper is re-conveyed by switching the paper conveyance direction by the conveyance roller provided in the double-sided printing apparatus, There is a risk of curling.
[0013]
In the image forming apparatus described in Patent Document 2, the rotation speed of the conveyance roller provided in the double-sided printing apparatus that comes into contact with the paper is made faster than the rotation speed of the conveyance roller provided immediately before the paper reaches the double-sided printing apparatus. Thus, there has been proposed a method for correcting the curl of the paper by applying tension to the paper when the paper is sandwiched between these rollers. However, in such a method, the conveyance roller provided in the double-sided printing apparatus contacts the paper from above, so that the upward curling of the paper that may cause paper jam at the entrance of the paper discharge path is eliminated. On the contrary, there is a possibility of promoting.
[0014]
The present invention has been made in view of the above points, and when the paper stored in the temporary storage portion is discharged, the paper is surely directed in the paper discharge path direction, and stable paper transport performance can be obtained. An object is to provide a printing apparatus.
[0015]
[Means for Solving the Problems]
In order to solve the above-described problem, the present invention provides a double-sided printing apparatus in which one side of a sheet is printed and the other side is continuously printed by switching the conveyance direction of the sheet. A temporary storage unit that temporarily stores the paper on which the surface is printed, a paper entrance path that feeds the paper on which one side is printed into the temporary storage unit, and a paper discharge path that is provided adjacent to the paper entrance path And a drive roller that is provided at the entrance of the temporary storage unit and discharges the paper fed into the temporary storage unit toward the paper discharge path, and the paper discharged between the drive roller and the discharge roller And a driven roller in which an offset amount with respect to the drive roller is set so that the leading edge of the paper to be directed is directed to the paper discharge path.
[0016]
According to this configuration, the paper discharged from the temporary storage unit is correctly transported toward the paper discharge path without going to the paper entrance path, so that no paper jam occurs at the entrance of the paper discharge path. In this way, the drive roller and the follower roller used for switching the paper transport direction can be used to ensure that the paper is directed in the paper discharge path direction, so a special means is added separately. Therefore, it is possible to provide a double-sided printing apparatus that is inexpensive and can obtain a stable paper conveyance performance with a simple configuration.
[0017]
The driven roller is separated from the drive roller only when a sheet enters the temporary storage unit, and moves so that the offset amount at the time of discharge decreases as the paper is separated from the drive roller. It was.
[0018]
If the driven roller is in contact with the driving roller with the offset amount when the paper is discharged as it is, there is a risk that the driven roller may interfere with the conveyance of the paper fed into the temporary storage unit. Therefore, according to the above configuration, the driven roller moves away from the driving roller when entering the paper and moves so that the offset amount is reduced. Therefore, the presence of the driven roller becomes an obstacle when the paper is fed into the temporary storage unit. Paper transport is not delayed and paper jams do not occur.
[0019]
Further, a paper guide member for opening and closing the outlet is provided at the outlet of the paper entrance path.
[0020]
According to this configuration, when the paper stored in the temporary storage unit is discharged, even if the upward curling of the paper is not corrected by the driving roller and the driven roller, the paper hits the paper guide member. Thus, the sheet can be reliably conveyed to the sheet discharge path side. Accordingly, it is possible to further improve the paper conveyance performance of the duplex printing apparatus.
[0021]
The paper guide member opens the outlet of the paper entrance path when the driven roller is separated from the drive roller, and closes the exit of the paper entrance path when the driven roller contacts the drive roller.
[0022]
According to this configuration, it is possible to perform highly efficient paper conveyance both when the paper enters the temporary storage unit and when the paper is discharged from the temporary storage unit. It becomes possible to provide a high-performance duplex printing apparatus.
[0023]
Further, the opening / closing operation of the paper guide member is performed according to the movement operation of the driven roller.
[0024]
According to this configuration, the opening and closing of the paper guide member and the movement of the driven roller can be performed by one actuator, so that the configuration can be made inexpensive and easy to control.
[0025]
Further, the opening and closing operation of the paper guide member is performed independently of the movement operation of the driven roller.
[0026]
According to this configuration, since the opening / closing operation of the paper guide member does not depend on the movement operation of the driven roller, it is possible to cope flexibly even when the paper transport procedure is changed variously.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[0028]
First, a double-sided printing apparatus according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic cross-sectional view showing a schematic structure of a paper conveyance direction switching unit, showing a state when paper is fed into an intermediate tray which is a temporary storage unit of a duplex printing apparatus, and FIG. It is model sectional drawing which shows a state when it discharges | emits from a tray. FIG. 3 is a schematic cross-sectional view of the main part showing details of the state of conveyance of the sheet with respect to the intermediate tray. Since the basic configuration of this embodiment is the same as the conventional structure introduced in FIGS. 6 to 8, the same reference numerals are given to the components common to the conventional structure, and the description will be omitted.
[0029]
The roller guide 9 a in which the shaft 6 a of the driven roller 6 is accommodated is provided with an inclination from the direction perpendicular to the intermediate tray 2. As a result, the offset amount D set between the driven roller 6 and the driving roller 5 decreases as the driven roller 6 moves away from the driving roller 5, and the offset amount D increases as the driven roller 6 approaches the driving roller 5. In this way, when the offset amount D increases and the driven roller 6 comes into contact with the driving roller 5, the leading edge of the paper that is sandwiched between the driving roller 5 and the driven roller 6 and is discharged from the intermediate tray 2 is the paper discharge path 4. To become oriented.
[0030]
Here, the details of the conveyance state of the sheet with respect to the intermediate tray 2 will be described with reference to FIG. In FIG. 3A, when the paper P enters the intermediate tray 2 through the paper entrance path 3, the driven roller 6 is separated from the driving roller 5, and the driving roller 5 rotates in the clockwise direction. At this time, even when the paper P curls upward in the direction of the paper entrance path 3, it enters the intermediate tray 2 without any particular inconvenience.
[0031]
Subsequently, when the paper P is discharged from the intermediate tray 2, as shown in FIG. 3B, the driven roller 6 contacts the drive roller 5 and the drive roller 5 rotates counterclockwise. When the driven roller 6 comes into contact with the driving roller 5, the offset amount D is set as described above, so that the driven roller 6 is positioned on the paper discharge path 4 side with respect to the driving roller 5. Then, the sheet P enters the nip formed by contact between the driving roller 5 and the driven roller 6 and is sandwiched between the two rollers so that the sheet P is curled downward. The leading edge of the paper P to be directed is directed to the paper discharge path 4.
[0032]
In this way, the paper P discharged from the intermediate tray 2 is correctly conveyed toward the paper discharge path 4 without going to the paper entry path 3, so that a paper jam occurs at the entrance of the paper discharge path 4. There is no. As described above, the drive roller 5 and the driven roller 6 used for switching the transport direction of the paper P can be used to ensure that the paper P is directed in the direction of the paper discharge path 4. It is possible to provide the double-sided printing apparatus 1 which is inexpensive and can obtain a stable paper conveyance performance with a simple configuration without adding special means.
[0033]
Further, if the driven roller 6 is in contact with the driving roller 5 with the offset amount D when the paper is discharged as it is, there is a risk that the driven roller 6 may interfere with the conveyance of the paper P fed to the intermediate tray 2. Therefore, according to the above configuration, the driven roller 6 moves away from the driving roller 5 when the paper enters, and the offset amount D is reduced. Therefore, when the paper P is fed to the intermediate tray 2, the driven roller 6 There is no obstacle to the presence of paper conveyance or paper jam.
[0034]
Subsequently, a double-sided printing apparatus according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a schematic cross-sectional view showing a schematic structure of the paper transport direction switching unit, showing a state when the paper is fed into an intermediate tray which is a temporary storage unit of the double-sided printing apparatus, and FIG. FIG. 4 is a schematic cross-sectional view illustrating a state when the medium is discharged from an intermediate tray of the printing apparatus. The basic configuration of this embodiment is the same as that of the conventional structure introduced in FIGS. 6 to 8 and the first embodiment described with reference to FIGS. Are denoted by the same reference numerals, and description thereof is omitted.
[0035]
A paper guide member 10 for opening and closing the outlet is provided at the outlet portion of the paper entrance path 3 so that the paper guide member 10 can rotate on a vertical plane around one point. The sheet guide member 10 is connected to a plunger 7 a of a solenoid 7 provided above the driven roller 6 via a link 11. Since the paper guide member 10 and the driven roller 6 are connected to the solenoid 7 via links, the paper guide member 10 is opened and closed according to the movement operation of the driven roller 6.
[0036]
When the paper enters the intermediate tray 2, the driven roller 6 is separated from the driving roller 5 and the paper guide member 10 opens the outlet of the paper entrance path 3 (see FIG. 4). 10 is conveyed along the upper surface. Further, when the paper is discharged from the intermediate tray 2, the driven roller 6 comes into contact with the driving roller 5 and the paper guide member 10 closes the outlet of the paper entrance path 3 (see FIG. 5). The paper is directed toward the paper discharge path 4 without going to the paper entrance path 3.
[0037]
By providing the paper guide member 10 in this way, even if the upward curling of the paper P is not corrected by the driving roller 5 and the driven roller 6, the paper P hits the paper guide member 10 and the paper It can be reliably conveyed to the discharge path 4 side. Therefore, it is possible to further improve the paper conveyance performance of the duplex printing apparatus 1.
[0038]
Further, when the driven roller 6 is separated / contacted with the driving roller 5, the sheet guide member 10 opens / closes the exit of the sheet entrance path 3, so that the sheet P enters the intermediate tray 2, and the intermediate tray 2. High-efficiency paper conveyance can be performed both when the paper is discharged from the printer. Thereby, paper conveyance performance is further improved, and it is possible to provide a high-performance double-sided printing apparatus 1.
[0039]
Furthermore, since the opening / closing operation of the paper guide member 10 and the movement operation of the driven roller 6 can be performed by the single solenoid 7, it is possible to provide a configuration that is inexpensive and easy to control.
[0040]
Note that by using an actuator dedicated to the paper guide member 10, the opening and closing operation of the paper guide member 10 may be performed independently of the movement operation of the driven roller 6. In this case, since the opening / closing operation of the paper guide member 10 does not depend on the movement operation of the driven roller 6, even when the paper transport procedure is changed variously, it is possible to respond flexibly.
[0041]
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.
[0042]
【The invention's effect】
According to the above configuration of the present invention, the paper discharged from the temporary storage unit is correctly transported toward the paper discharge path without going to the paper entrance path, so that a paper jam occurs at the entrance of the paper discharge path. There is no. In this way, the drive roller and the follower roller used for switching the paper transport direction can be used to ensure that the paper is directed in the paper discharge path direction, so a special means is added separately. Therefore, it is possible to provide a double-sided printing apparatus that is inexpensive and can obtain a stable paper conveyance performance with a simple configuration.
[0043]
Further, if the driven roller is in contact with the driving roller with the offset amount when the paper is discharged as it is, there is a possibility that the driven roller may interfere with the conveyance of the paper fed into the temporary storage unit. Since the roller moves away from the drive roller when entering the paper and the offset amount is reduced, when the paper is sent to the temporary storage unit, the presence of the driven roller becomes an obstacle and paper conveyance is delayed or paper jam occurs. It does not occur.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing a schematic structure of a paper transport direction switching unit of a duplex printing apparatus according to a first embodiment of the present invention, showing a state when paper is fed into an intermediate tray. 2 is a schematic cross-sectional view showing a state when a sheet is discharged from the intermediate tray shown in FIG. 1. FIG. 3 is a schematic cross-sectional view of a main part showing details of a state of paper transport to the intermediate tray shown in FIG. FIG. 4 is a schematic cross-sectional view showing a schematic structure of a paper transport direction switching unit of a duplex printing apparatus according to a second embodiment of the present invention, showing a state when paper is fed into an intermediate tray. 5 is a schematic cross-sectional view showing a state when paper is discharged from the intermediate tray shown in FIG. 4. FIG. 6 is a schematic cross-sectional view showing a schematic structure of a paper transport direction switching portion of a conventional double-sided printing apparatus. When paper is fed into the intermediate tray FIG. 7 is a schematic cross-sectional view showing a state when paper is discharged from the intermediate tray shown in FIG. 6. FIG. 8 is a detailed view of paper when paper is discharged from the intermediate tray shown in FIG. Cross-sectional view of the main part of the model showing the state [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Duplex printing apparatus 2 Intermediate tray 3 Paper entrance path 4 Paper discharge path 5 Driving roller 6 Driven roller 6a Shaft 7 Solenoid 7a Plunger 8, 11 Link 9 Support member 9a Roller guide 10 Paper guide member

Claims (6)

In a double-sided printing device that enables printing on the other side by switching the transport direction of the paper after one side of the paper is printed,
A temporary storage unit for temporarily storing paper on which one side is printed;
A paper entry path for feeding paper on which one side is printed to the temporary storage unit;
A paper discharge path provided adjacent to the paper entry path;
A driving roller provided at an entrance of the temporary storage unit and discharging the paper fed into the temporary storage unit toward the paper discharge path;
And a driven roller having an offset amount with respect to the drive roller so that the paper to be discharged is sandwiched between the drive roller and the leading end of the discharged paper is directed to the paper discharge path. A double-sided printing apparatus characterized by that. The driven roller is separated from the drive roller only when a sheet enters the temporary storage unit, and moves as the offset amount at the time of discharge decreases as the paper is separated from the drive roller. The double-sided printing apparatus according to claim 1. The double-sided printing apparatus according to claim 1, wherein a paper guide member for opening and closing the outlet is provided at an outlet portion of the paper entrance path. The paper guide member opens an exit of the paper entrance path when the driven roller is separated from the drive roller, and closes an exit of the paper entrance path when the driven roller contacts the drive roller. Item 4. The double-sided printing apparatus according to item 3. The double-sided printing apparatus according to claim 4, wherein the opening and closing operation of the paper guide member is performed according to a movement operation of the driven roller. The double-sided printing apparatus according to claim 4, wherein the opening and closing operation of the paper guide member is performed independently of the movement operation of the driven roller.

Images