JPH04345433A - Paper feeder for image forming device - Google Patents

Abstract

PURPOSE:To enable changeover from a position for a paper feeding casette to a position for a mass paper supplying device without detaching a bottom plate life lever by displacing and fixing the lift lever from the position for the paper feeding casette to the position for the mass paper supplying device. CONSTITUTION:A lift lever 2 is attached to a shaft 21 with a stepped screw 22 and moved up and down by turning the shaft 21, and when the lever 2 is lifted up, a bottom plate 23 is lifted up to convey record paper 4 with a contacted pick up roller 3. On the bottom plate lift lever 2, push balls 2a, 2b are provided respectively, and on the shaft 21, a through hole 21a fitted to the push balls is provided. When a paper feeding casette is used, the push ball 2a is inserted in the through hole 21a to fix the lever 2 in a paper feeding casette position, and when a mass paper supplying device is used, the push ball 2b is inserted in the through-hole 21a and fixed in a release condition. Hence at the time of changeover, the lever 2 can be turned and fixed without detaching the screw 22, and thereby operability can be improved and the loss of the lever 2 or the screw 22 can be eliminated.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeder used in image forming apparatuses such as laser printers, copying machines, and facsimile machines to which a large-volume paper feeder can be attached.

0002

2. Description of the Related Art Laser printers, for example, are very convenient when printing a large number of sheets in a row, so they have been put into practical use and equipped with a large-volume paper feeder.

Conventionally, when attaching a large-volume paper feeder to a laser printer, a separate paper feed port was provided exclusively for the large-volume paper feeder, or a cassette paper feed port was opened by removing the bottom plate lift lever of the laser printer main body. I have been using it.

[0004] Recently, an increasing number of large-capacity paper feeders have become options that can be installed by users. Furthermore, many of these printers are attached to the cassette paper feed slot of a laser printer, and the paper is fed from a large-volume paper feed device instead of the paper cassette.

[0005] In this case, the bottom plate lifting lever located at the cassette paper feed port of the main body of the laser printer gets in the way and must be removed.

[0006]

[Problems to be Solved by the Invention] Conventionally, this bottom plate lifting lever has been attached with a fastening member such as a screw.
After removal, the bottom plate lifting lever and fastening members such as screws had to be managed by the user, and there was a great risk of losing them.

[0007] The present invention provides a mechanism that allows the user to release the bottom plate lift lever by hand without removing the fastening member, thereby making it possible to use a large-volume paper feeder that uses the paper feed port of the main body in common with a cassette. The goal is to improve the operability when installing it in a printer.

[0008]

[Means for Solving the Problems] The present invention solves the above-mentioned problem by providing a bottom plate lift lever for pressing recording paper against a pickup roller when feeding paper from a paper feed cassette in a paper feeding device of an image forming apparatus. This is solved by providing a position fixing mechanism that fixes the lever in two positions, and when feeding paper from the large-volume paper feeder, the lever can be moved and fixed from the paper cassette position to the large-volume paper feeder position. did.

Although it is conceivable to provide an electromagnet as a position fixing mechanism, it is also possible to rotatably attach the bottom plate lifting lever to the mounting shaft with a screw, and to fix the bottom plate lifting lever to the mounting shaft at the two positions mentioned above. The problem can be reliably solved by providing the bottom plate lift lever and the recess respectively on either the bottom plate lifting lever or the mounting shaft.

0010

[Operation] According to the present invention, the position fixing mechanism provided on the bottom plate lift lever and its mounting shaft keeps the lever in a predetermined position when feeding paper from a cassette and when feeding paper from a mass paper feeder. The lever is fixed and can be easily moved without removing the fastening member when changing its position, improving operability when attaching the large-volume paper feeder to the image forming apparatus, and also improving the ease of operation when attaching the large-volume paper feeder to the image forming apparatus. There is no longer any danger of losing fastening parts.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be explained based on the embodiments shown in the drawings.

FIG. 1 is a schematic diagram of a laser printer used in this embodiment.

The recording paper 4 is pressed from the paper feeder 1 against the pickup roller 3 by the bottom plate lifting lever 2 and is fed in the direction of the pair of registration rollers. The latent image carrier is conveyed to the latent image carrier. The photoconductor 6 is driven to rotate counterclockwise in the figure, and at this time, the surface is charged by the charger 7 and irradiated with laser light from the laser optical system 8 to form an electrostatic latent image on the photoconductor. . This latent image is transferred to the developing device 9.
When the toner passes through the toner, the toner forms a visible image, and this visible image is transferred to the recording paper 4 conveyed to the photoreceptor 6 by the transfer charger 10, and the transferred visible image on the recording paper is fixed by the fixing device 11. Ru. On the other hand, residual toner is removed from the photoreceptor 6 after the visible image has been transferred by a cleaning device having a cleaning blade 12. The toner removed from the photoreceptor 6 is collected and stored in a toner collection tank 13. The recording paper 4 discharged from the fixing device 11 is stored as is in the paper discharge section 14 in the case of single-sided recording, and guided to the double-sided conveying roller pair 16 by a rotatable double-sided entrance guide 15 in the case of double-sided recording. . The recording paper 4 is conveyed by the double-sided conveyance roller pair 16 to a reversing roller pair 17 that rotates so as to convey the recording sheet 4 toward the paper feeder, and passes through a reversal sensor 18 . After a predetermined period of time after the recording paper 4 passes the reversal sensor 18, the reversing roller pair 17 changes its rotation direction and further switches the rotatable reversing guide 19 to transport the recording paper 4 in the direction of the registration roller pair. The recording paper 4 is again fed to the pair of registration rollers 5, and the timing is determined by the pair of registration rollers 5, and the recording paper 4 is delivered to the photoreceptor 6.
The toner image is transferred and fixed onto the recording paper 4 through the same procedure as described above. At this time, since the opposite side of the recording paper 4 contacts the photoreceptor 6 than when it is fed from the paper feeding device 1, double-sided recording is performed on the recording paper 4. After the recording paper 4 on which double-sided recording has been performed passes through the fixing device 11, it is delivered to the paper discharge section 1 by the double-sided entrance guide 15.
It is discharged and stored at 4.

FIG. 2 is a schematic diagram of the structure when the user removes the lower paper feed cassette from the laser printer and attaches the mass paper feed device 20. Conventionally, at this time, the bottom plate lifting lever is removed and the user manages it together with the fastening members such as screws.

FIG. 3 shows a friction separation type paper feeding mechanism used in this laser printer. The bottom plate lifting lever 2 is fastened to a shaft 21 by a stepped screw 22, and when the shaft 21 rotates, the bottom plate lifting lever 2 moves up and down, and when the lever 2 rises, the bottom plate 23 is lifted up, and a pickup roller 3 rotates the recording paper 4. The recording paper 4 is conveyed to a pair of registration rollers by the rollers.

In the present invention, as shown in FIG. 4 when the bottom plate lifting lever 2 and its mounting shaft are viewed from above, the bottom plate lifting lever 2 made of a molded member is provided with a ball projection 2a and a ball projection 2b, and the bottom plate lifting lever 2 is provided with a ball projection 2a and a ball projection 2b. A through hole 21a suitable for ejecting a ball when the lever 2 is fastened to the shaft 21 with a step screw 22 is made in a part of the shaft 21. When using the paper feed cassette, the protruding ball 2a enters the through hole 21a as shown in FIG. 4, and the position of the lever is fixed.

As shown in FIG. 6, in which the lever 2 is rotated from the paper feed cassette position, when using the mass paper feed device, the ball 2b enters the through hole 21a, and the lever 2 is fixed in the released state. be done. When switching between using a paper feed cassette and using a mass paper feeder, the screw is not removed when the lever is rotated.

After all, when using the paper feed cassette 1, the bottom plate lifting lever 2 is used in the state shown in FIG. 4, and when using the large-volume paper feed device 20 at the same lower paper feed port, it is used in the state shown in FIG. to cancel.

[0019]

[Effects of the Invention] According to the present invention, it is possible to install a large-volume paper feeder without removing the bottom plate lifting lever, which improves operability, and also prevents problems that may occur when the user manages the removed bottom plate lifting lever, screws, etc. Risks such as loss can be avoided.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a laser printer according to an embodiment of the present invention with a paper feed cassette attached to a lower paper feed port.

FIG. 2 is a schematic configuration diagram of the laser printer according to the present embodiment in a state where a large-volume paper feed device is attached to the lower paper feed port.

FIG. 3 is a schematic diagram of a friction separation type paper feeding mechanism according to the present embodiment.

FIG. 4 is a plan view of the bottom plate lift lever and its mounting shaft according to the present invention when the paper feed cassette is used.

FIG. 5 is a sectional view of the lever and shaft in FIG. 4 with their orientations changed by 90 degrees.

FIG. 6 is a plan view of the bottom plate lift lever and its mounting shaft according to the present invention when the large-volume paper feeder is used.

FIG. 7 is a sectional view of the lever and shaft of FIG. 6 with their orientations changed by 90 degrees.

[Explanation of symbols]

2 Bottom plate lift levers 2a, 2b
Ball projection 21 Shaft 21a Through hole 22 Step screw

Claims (2)

[Claims] Claim 1: In a paper feeding device of an image forming apparatus, which has a plurality of paper feeding ports and in which a large amount of paper feeding device can be installed in addition to the paper feeding cassette at the lowest end of the paper feeding ports, A position fixing mechanism is provided to fix the bottom plate lift lever in two positions to press the recording paper against the pickup roller during paper feeding, and when feeding paper from the large-volume paper feeder, the lever can be moved to the paper feeding cassette position. A paper feeding device characterized in that it can be moved from the position to a position for a large quantity paper feeding device and fixed therein. 2. A bottom plate lifting lever is rotatably attached to the mounting shaft with a screw, and a protrusion and a recess for fixing the bottom plate lifting lever to the mounting shaft at the two positions are connected to the bottom plate lifting lever and the mounting shaft. 2. A paper feeding device according to claim 1, wherein the paper feeding device is provided in either one of the two.