JP2001122531A - Image forming device - Google Patents

Abstract

(57) Abstract: An image forming apparatus capable of performing double-sided printing without downsizing the image forming apparatus, increasing installation space in a horizontal direction, and causing no malfunction of a user. An opening communicating with a conveyance path for double-sided printing on a side surface of a transfer paper table, and a normal reversing roller capable of normal reversing near the opening.
And a tray 19 which can be mounted in a state protruding from the side of the apparatus at the opening, and discharges the transfer paper transported to the transport path 16 for double-sided printing onto the tray 19 by forward rotation of the forward / reverse roller 18, and forward rotation roller It is supplied to the registration roller 10 by reversing 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a printer and a copying machine, and more particularly to an image forming apparatus having a conveyance path for double-sided printing and a sheet reversing mechanism for enabling double-sided printing.

[0002]

2. Description of the Related Art A conventional image forming apparatus provided with a sheet reversing mechanism for double-sided printing includes, for example, a configuration in which a reversing mechanism is provided on an upper surface of a fixing device and is conveyed to a lower surface of the fixing device (a first reversing configuration, Japanese Patent Application Laid-Open No. 3-143850), a configuration in which a sheet reversing mechanism is provided which conveys the sheet from the discharge port of the fixing device to the lower surface and folds it into a substantially U-shape on the upstream side in the conveying direction of the registration roller (second).
F16832), a configuration in which the sheet is conveyed from the fixing device to the apparatus discharge section and conveyed to the conveyance path for double-sided printing discharged onto a discharge tray (third reversal configuration, Japanese Patent Laid-Open No. 5-116833).
No. Gazette).

[0003]

In the social environment in which global environmental protection activities have been activated in recent years, the importance of image forming apparatuses capable of double-sided printing as a resource saving function has been increasing. Emphasis is placed on achieving compactness and low cost while providing a double-sided printing transport path and a reversing mechanism.

However, in the first conventional reversing structure, there is a problem that the entire apparatus becomes large and large because the reversing mechanism is provided inside the apparatus on the upper surface of the fixing unit. The provision of the conveyance path for double-sided printing and the reversing mechanism on the lower surface of the container causes a problem that the entire apparatus becomes large and large, and the third reversing mechanism does not have the reversing mechanism inside the apparatus, but discharges to the side. The installation space for the tray increases the horizontal installation space, especially when a paper feeder such as a cassette containing paper or a manual feed tray is provided on the side opposite to the discharge tray so as to protrude. There is a problem that the installation space in the direction increases, and the user once malfunctions because the sheet is once discharged to the discharge tray.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a paper supply port on the side of the apparatus upstream of the registration roller in the conveying direction and a paper stored in the paper supply port. A sheet feeding device, a double-sided printing conveyance path from the fixing device to the registration roller is formed, and an image forming apparatus is provided with a reversing mechanism for reversing a sheet on the double-sided printing conveyance path. An opening communicating with the printing conveyance path, a normal reversing roller capable of normal reversal near the opening, a tray communicating with the opening, and a normal rotation of the sheet conveyed to the double-sided printing conveyance path by the normal reversing roller. And control means for controlling the sheet to be supplied to the double-sided printing conveyance path by reversing the normal rotation roller.

With this configuration, the size of the image forming apparatus can be reduced because no reversing mechanism is provided inside the image forming apparatus, and the opening and the tray are provided on the side surface on which the sheet feeding device is mounted. Therefore, the installation space in the horizontal direction does not increase, and the user does not malfunction.

Further, according to the present invention, the opening is provided in the vicinity of the paper supply port, and the paper feeder and the tray are integrated, or the opening is provided below the paper supply port. , The sheet feeding device and / or the tray can be opened and closed on the side of the image forming apparatus, or the sheet feeding device and / or the tray can be opened and closed.
Alternatively, the image forming apparatus may be configured such that the tray is detachable from the image forming apparatus, or a manual tray is used as the paper feeding apparatus, the opening is the same as the paper supply port, and the manual tray is the tray. This is also an effective means.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating an image forming apparatus provided with a conveyance path for double-sided printing and a reversing mechanism according to the present invention.
A laser unit 2, a charger 3, a static eliminator 4, a cleaning unit 5, a developing unit 6, and a transfer roller 11 are disposed around the transfer paper 8, and the transfer paper 8 stored in a transfer paper table 7 protruding from the side of the main body is The sheet is discharged via a sheet feed roller 9, a registration roller 10, a transfer roller 11, a fixing roller 12, and a discharge roller 13.

On the downstream side of the fixing roller 12 in the conveying direction, a branch guide 14 and a double-sided conveying roller 1
5, double-sided conveyance path 16, reversing switch 17, forward reversing roller 18,
A tray 19 and a branch guide 20 are provided.

When a double-sided mode is selected and printing is started by an external operation, a double-sided mode signal is supplied. First, the transfer paper 8 on the transfer paper base 7 is transferred to the paper feed roller 9 for one-sided transfer.
And the resist is conveyed to the stopped registration roller 10. Then, the registration roller 10 is rotated in time for image formation, and the transfer roller 11 and the drum 1 are rotated.
The toner latent image on the drum 1 is transferred to the transfer paper 8 and transferred to the fixing roller 12, where the toner latent image on the transfer paper 8 is fixed to the transfer paper by heat and pressure.

After the fixing, the branch guide 14 guides the sheet to the double-sided conveyance entrance on the lower surface. 1 is arranged at the time of single-sided transfer in FIG. 1, and the operation at the time of double-sided transfer will be described with reference to FIG.

FIG. 2 is a configuration diagram of the fixing device 12 on the downstream side in the transport direction at the time of double-side transfer, and the branch guide 14 rotates in conjunction with the operation of a solenoid or the like. Since the double-sided signal is received, the solenoid is energized, and the branch guide 14 rotates to guide the double-sided conveyance entrance on the lower surface of the fixing unit as shown in FIG. The transfer paper 8 enters from the entrance of the two-sided conveyance path 16 and passes through the two-sided conveyance roller 15 to the reversing switch 17. The reversing switch 17 is rotated so as to convey the normal reversing roller 18 toward the tray 19, and stops after rotating for a predetermined time. Then, after turning the branch guide 20, it has a function of rotating the forward / reverse roller 18 in the reverse direction. Then, the transfer paper 8 presses the reversing switch 17 and enters the normal reversing roller 18. A tray 19 serving as a reversing guide is provided on the lower surface of the transfer paper table 7, and the tray 19 is mounted on the transfer paper table 7 so that the transfer paper 8 can be conveyed to a gap between the transfer paper table 7 and the tray 19.
It communicates with the opening after 18.

Therefore, the transfer paper 8 passes through the forward / reverse roller 18 and on the tray 19. Then, the forward / reverse roller 18 is stopped while the rear end of the transfer paper 8 is slightly nipped with the forward / reverse roller 18 for a predetermined time of the reverse switch 17.

The next operation will be described with reference to FIG. FIG. 3 is a diagram showing the configuration of the reverse of double-sided conveyance and the registration roller 10. When the forward / reverse roller 18 stops, the branch guide 20 rotates in the conveyance direction toward the registration roller 10 almost at the same time as in FIG. Then, the forward / reverse roller 18 rotates in the reverse direction, transports the transfer paper 8 toward the registration roller 10, and starts an image forming operation on the back surface. Of course, when the transfer paper 8 passes over the guide, the branch guides 14 and 20 are rotated to the original positions. Then, the transfer paper 8 on which double-side printing has been performed is discharged from the image forming apparatus by the discharge roller 13.

In this embodiment, the transfer paper table 7 can be mounted in a state protruding from the side of the apparatus of the image forming apparatus main body, and the transfer path 16 for the double-sided printing from the fixing roller 12 to the registration roller 10 is provided.
In the image forming apparatus, an opening communicating with the conveyance path for double-sided printing, a forward / reverse roller 18 capable of forward / reverse rotation in the vicinity of the opening, and an opening protruding from the side of the apparatus are provided in the mounting side of the transfer paper table 7. A transfer tray 8 provided on a transfer tray 16 for double-sided printing is discharged to the tray 19 by forward rotation of the forward / reverse roller 18, and is transported to the registration roller 10 by reversal of the forward / reverse roller 18. It is characterized by.

With this configuration, it is not necessary to provide a space for accommodating the inverted transfer paper 8 in the image forming apparatus, so that the entire apparatus can be reduced in size, and the transfer paper printed on one side of the paper supply side can be used. Since the sheet 8 is temporarily discharged, a malfunction of the user does not occur. Further, in the case where the paper discharge tray is provided on the upper surface of the image forming apparatus main body to perform face-down paper discharge, there is no need to provide a tray on a surface opposite to the side surface on which the paper supply device is installed. In the horizontal direction can be saved. In this embodiment, the case where the transfer paper table 7 and the tray 19 are projected has been described.

Further, as in the present embodiment, the tray 19 is integrally provided on the lower surface of the transfer paper table 7 as a paper feeding device, so that the setup can be easily performed. Note that the tray 19 and the transfer paper table 7 may be configured to be openable and closable on the side of the image forming apparatus, or may be detachable, so that space saving when not in use can be realized. become.

Further, a manual tray may be provided in place of the transfer paper table 7, and the manual tray may be used also as the tray 19. With such a configuration, a special member is not newly provided at the time of double-sided printing. It can be realized.

FIG. 4 shows a multi-stage paper feeder 26 (shown in FIG.
FIG. 9 is a configuration diagram in a case where the sheet feeding device of the lower stage is omitted), in which the reversing conveyance path 22 and the vertical conveyance path 25 from the sheet feeding device 26 are merged on the sheet feeding side of the normal reversing roller 18. Can be achieved. In the present embodiment, the description has been made with reference to the drawing in which the transfer paper table 7 is opened to the paper feed setting state. However, even when the transfer paper table 7 is By configuring the guide of the opening so that the transfer paper 8 conveyed from the main body is guided to the tray 19, the transfer paper conveyed from the paper feeding device 26 by the rotation of the supply roller 23 can be printed on both sides. Become like

As in the present embodiment, the tray 19 is
, The forward / reverse roller 18 can also serve as a transport roller for transporting the transfer sheet from the lower sheet feeder 26 to the registration roller 10.
Further, as is common even when the paper feeding device 26 is not provided, the paper may be skewed during duplex printing, but the leading edge of the transfer paper 8 transported from the duplex transport path 16 is correct. The skew can be corrected when entering the reversing roller 18, so that the alignment plates can be omitted at both ends in the width direction of the transfer sheet. Further, the timing may be controlled so that the forward / reverse roller 18 reaches the registration roller 10 at the time of double-sided printing or at the time of transfer of the transfer paper from the lower paper feeding device 26. The paper feed timing can be controlled only by the apparatus main body.

[0021]

The image forming apparatus according to the present invention has a tray on which the paper conveyed to the conveyance path for double-sided printing is provided on the installation surface of the paper feeding device, so that the transfer paper is inverted in the image forming apparatus. Since there is no transfer unit, the transfer quality of JAM, skew, and the like can be improved, and a compact, small-footprint, low-cost image forming apparatus can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an image forming apparatus of the present invention.

FIG. 2 is a partially enlarged view of the image forming apparatus of the present invention.

FIG. 3 is a partially enlarged view of the image forming apparatus of the present invention.

FIG. 4 is a view showing another embodiment of the image forming apparatus of the present invention.

[Explanation of symbols]

 1: Drum 2: Laser unit 3: Charger 4: Static eliminator 5: Cleaning unit 6: Developing device 7: Transfer paper table 8: Transfer paper 9: Paper feed roller 10: Registration roller 11: Transfer roller 12: Fixing roller 13 : Ejection roller 14: Branch guide 15: Double-sided transport roller 16: Double-sided transport path 17: Reverse switch 18: Forward / reverse roller 19: Tray 20: Branch guide

Claims (6)

[Claims] 1. A double-sided printing conveyance path from a fixing device to the registration roller is provided with a paper supply port and a paper supply device in which the paper is stored in the paper supply port on the side of the apparatus upstream of the registration roller in the conveyance direction. An image forming apparatus provided with a reversing mechanism for reversing a sheet on the two-sided printing conveyance path, wherein an opening communicating with the two-sided printing conveyance path on a side surface of the apparatus, Rollers, a tray communicating with the opening, and a sheet conveyed to the double-sided printing conveyance path is discharged to the tray by normal rotation of the normal reversing roller, and the double-sided printing conveyance is performed again by reversing the normal rotation roller. An image forming apparatus, comprising: control means for controlling supply to a road. 2. The image forming apparatus according to claim 1, wherein said opening is provided near said sheet supply port, and said sheet feeding device and said tray are integrated. 3. The image forming apparatus according to claim 1, wherein said opening is provided below said paper supply port. 4. The image forming apparatus according to claim 1, wherein the sheet feeding device and / or the tray can be opened and closed on a side surface of the image forming device. 5. An image forming apparatus according to claim 1, wherein said sheet feeding device and / or tray is detachable from said image forming device. 6. A manual feeding tray is used as the paper feeding device.
6. The image forming apparatus according to claim 1, wherein the opening is the same as the paper supply port, and the manual tray is the tray.