JP2001154421A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device constituted so that a high-quality image is formed and carrying quality is enhanced by drastically improving the meandering of an intermediate tray device and a jam due to the meandering by simple constitution at both-surface carrying time. SOLUTION: A sheet matching member 16 is set at a 1st sheet matching position where space becomes larger than sheet width when a sheet is carried in, set at a 2nd sheet matching position where the space becomes smaller than the sheet width when the sheet is matched and set at a 3rd sheet matching position where the space becomes almost identical to the sheet width when the sheet is carried out.

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, a copying machine, and a facsimile, and more particularly to an image forming apparatus having an intermediate tray device and capable of performing both-side printing.

[0002]

2. Description of the Related Art Conventionally, regarding sheet alignment members,
Many technologies have been announced for the duplexer of copiers, tray alignment of cassettes and sorters, and paper feeder and stocker for printing machines, most of which are used as sheet alignment technology for stacking sheets. Are known.

In this sheet bundle alignment, the sheet alignment member is aligned at a position slightly larger than the sheet width. The reason why the sheet bundle cannot be set at a position smaller than the sheet width is that there is a problem that the driving motor of the sheet aligning member loses and locks or the end of the sheet is broken due to the stiffness of the sheet bundle.

[0004]

However, if the sheet aligning member is arranged at a position larger than the sheet width and aligned, the sheet aligning member is obliquely stocked between the sheet aligning members, and the skew is increased upon refeeding. was there. Also,
As the speed becomes higher, as the countermeasures that the alignment quality deteriorates due to the sheet rebounding by the sheet alignment member, the forward / backward speed of the sheet alignment member at the time of alignment is reduced, or a mechanism for alignment is added. Needed.

[0005] In the technique of stock alignment using a tray such as a sorter or the like, most of the sheet alignment techniques are used, and there is also a technique in which an alignment member is operated to be narrower than the sheet width. This technique is also a sheet bundle. As long as the above problem is unavoidable. Further, in the one-sided alignment, there is a problem in that the repulsive force of the sheet reaches the side of the forward / backward alignment, and the alignment deviation of the bite becomes large.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has an object to reversely accommodate a sheet having an image formed on a front surface, align the sheet, and then aim at image formation on the back surface. In an image forming apparatus having an intermediate tray device that repeats an operation of discharging for each sheet, a sheet aligning member that aligns sheets by repeating advance and retreat in a sheet direction according to loading and unloading of sheets to and from the intermediate tray device is provided. The sheet aligning member is set to a first sheet aligning position such that when the sheet is carried in, the first sheet aligning position has an interval larger than the sheet width;
An image forming apparatus that sets a second sheet alignment position that is smaller than the sheet width when aligning sheets and a third sheet alignment position that is substantially equal to the sheet width when unloading the sheet; It is what it was.

[0007] With such a configuration in which processing is performed for each cut sheet and the first to third sheet alignment positions are provided, skew is hardly caused, and sheet alignment can be realized simply and accurately.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an image forming apparatus of the present invention. In one-sided image formation, first, a sheet is sent out from a sheet feeding device 1, conveyed to a registration roller 3, and a developing unit 4 arranged around a photoreceptor 5. , Laser optical unit 6, charging unit 7,
Sent to an image forming unit such as a cleaning unit 8 and a transfer unit 9;
A one-sided image is formed. Then, the toner image sent to the fixing unit 10 and transferred is fixed to the sheet. Next, the branch lever 11 rotates toward the double-sided conveyance path 12 under the signal of the double-sided printing mode, and conveys the sheet to the double-sided portion.

The sheets conveyed to both sides are transported by a double-sided conveying path 12.
Then, the paper is sent to the reversing alignment unit 13 via the paper re-feed roller 14. When the sheet leaves the sheet re-feed roller 14, the sheet stops and the sheet aligning member 16 aligns the sheet in a direction perpendicular to the conveying direction.
Then, the forward feed roller 15 is moved to the sheet surface and is sent to the re-feed roller 14, and is sent to the registration roller 3 for the back surface image formation by the re-feed roller 14, and is sent to the image forming section of the photoconductor 5. A back side image is formed, discharged to the outside of the main body through the fixing unit 10,
Be stocked.

Here, the intermediate tray device is a double-sided conveying path.
12, re-feed roller 14, reversing alignment unit 13, sheet alignment member 1
6. Refers to the one including the forward feed roller 15, and is characterized in that a sheet is processed for each cut. Also, a sheet alignment member
As shown in FIG. 2, a pair of the sheet aligning members 16 are provided in a direction substantially perpendicular to the sheet conveying direction and have a substantially L-shaped or U-shaped cross section. Is moved in the direction to reduce the width, the alignment can be performed.

In the reversing alignment section 13 of the present invention, the sheet alignment member 16 is waiting at the home position, which is a position wider than the MAX size of the sheet during standby. When the sheet is conveyed to both sides after one-sided printing, the sheet aligning member 16
Moves to a position "sheet receiving position (first sheet alignment position)" 8 to 10 mm wider than the sheet width. When the sheet leaves the re-feed roller 14 and becomes free, the sheet aligning member 16 moves to a "sheet aligning position (second sheet aligning position)" which is 1 to 5 mm narrower than the sheet width. When the advance roller 15 moves to the sheet surface and is sent to the re-feed roller 14 and is sent to the registration roller 3 for forming the back surface image by the re-feed roller 14, the sheet alignment member 16 To the same position "sheet feeding position (third sheet alignment position)".

FIG. 2 is a sheet alignment operation diagram.
(A) is a “sheet alignment position (second sheet alignment position)” that is 2 mm narrower than the sheet width. At this time, the sheet state is such that the center of the sheet is slightly bent upward as shown in FIG. Both sides of the seat are bent upward. Before the sheet alignment, the sheet is obliquely stocked with some curl, but can be accurately aligned because it is narrower than the sheet width. If the sheet is too narrow, the seat becomes stiff and the motor torque increases as the sheet thickness increases. On the other hand, the smaller the size of the sheet misalignment of the sheet aligning member 16 after the retreat is, the more likely it is due to the repulsion of the sheet. For this reason, the state of whether or not the sheet slightly floats from the mounting table below the sheet is the most stable, and it is preferably about 2 to 3 mm narrower depending on the amount of curl of the sheet.

FIG. 3 is a view at the time of feeding. In order to re-feed the sheet from the "sheet alignment position (second sheet alignment position)", in order to reduce the load on the sheet alignment member 16, maintain the sheet feeding force, and prevent skew during re-feeding. Next, the sheet is moved to a "sheet feeding position (third sheet alignment position)" which is wider than the transfer sheet by 0 to 1 mm. Considering the variation of the sheet width, it is more preferably 0.5 to 1 mm.

Further, when the speed becomes higher, the moving speed from the "sheet aligning position (second sheet aligning position)" to the "sheet feeding position (third sheet aligning position)" becomes lower than the other moving speeds. Can be reduced.

When moving from the "sheet aligning position (second sheet aligning position)", the forward feed roller 15 is rotated to the sheet surface to hold the sheet, and then the "sheet feeding position (third sheet aligning position)". )) ", The deviation becomes better when re-feeding. As shown in FIG. 3B, if an aligning operation without the "sheet aligning position (third sheet aligning position)" of the related art is performed, the sheet is fed again in a skewed state as shown in FIG.

Then, the sheet is sent to the re-feed roller 14 by the forward feed roller 15 and is conveyed to the back side image formation. Thereafter, the sheet aligning member 16 moves to the “sheet receiving position (first sheet aligning position)” and waits for the sheet in the case of the continuous double-sided operation, repeats the above-described operation, and returns to the “home position” when the operation is completed. stand by. The “home position” may also be used as the “sheet receiving position (first sheet aligning device)”.

FIG. 4 is a flowchart for explaining the sheet alignment operation. The sheet aligning member 16 is waiting at the home position (Step 1), and when the sheet is fed from the sheet feeding device 1 with the duplex printing and the sheet size selection signal, the sheet aligning member 16 is moved to the first sheet aligning position. (Step 2), and when one sheet is detected as stock by the reversing alignment unit 13 (Step 3), the sheet alignment member 16 is moved to the second sheet alignment position and aligned (Step 4).
Thereafter, the sheet aligning member 16 moves to the third sheet aligning position (step 5), and the sheet is fed out and the process ends (step 6).

If a sheet conveyance error such as JAM occurs before the stock of step 3 is completed, the process returns to step 2 (B-1). If the number of sheets is one in step 6, the process returns to step 1 (A). If the number of sheets is continuous printing, the process returns to step 2 (B-2).

FIG. 5 is a diagram showing the results of an experiment in which 500 sheets of each size were passed through the image forming apparatus (FS-9000 made by Kyocera) as shown in FIG. 1 as a comparative evaluation experiment.
As can be seen from the figure, the matching operation of the present invention is good. In the experiment conditions, A is the conventional alignment, the first sheet alignment position is 9 mm wider than the sheet width, there is no second sheet alignment position, and the third sheet alignment position is 1 mm wider than the sheet width.
mm wide condition. And B is the alignment of the present invention;
The first sheet alignment position is 9 mm wider than the sheet width, the second sheet alignment position is 2 mm narrower than the sheet width, and the third sheet alignment position is 1 mm wider than the sheet width.

[0020]

As described above, according to the image forming apparatus of the present invention, the sheet aligning member is processed by the intermediate tray device for each cut, and is larger than the sheet width when the sheet is carried in. The first sheet alignment position is set to be the interval, the second sheet alignment position is set to be smaller than the sheet width when aligning the sheets, and the interval is substantially the same as the sheet width when unloading the sheet. By setting the third sheet alignment position, JAM due to skew or skew of the intermediate tray device in double-sided conveyance is greatly improved with a simple configuration, and an image forming apparatus that provides high-quality images and conveyance quality is provided. be able to.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating a second sheet alignment position state of the image forming apparatus of the present invention.

FIG. 3 is a diagram illustrating a third sheet alignment position state of the image forming apparatus of the present invention.

FIG. 4 is a diagram illustrating the operation of the sheet alignment member of the present invention.

FIG. 5 is a diagram showing a comparative evaluation of the image forming apparatus of the present invention.

[Explanation of symbols]

 1: Paper feeder 3: Registration roller 5: Photoconductor 4: Developing unit 6: Laser optical unit 7: Charging unit 8: Cleaning unit 9: Transfer unit 10: Fixing unit 11: Branch lever 12: Double-sided conveyance path 14: Re Paper feed roller 13: reverse alignment section 16: sheet alignment member 15: forward feed roller

Claims (3)

[Claims] 1. An image forming apparatus having an intermediate tray device that repeats an operation of storing a sheet having an image formed on a front surface thereof in an inverted manner, discharging the sheet for image formation on the rear surface after aligning the sheets, and for each sheet. A sheet aligning member for aligning the sheet by repeating advance and retreat in the sheet direction according to the loading and unloading of the sheet to the intermediate tray device is provided, the sheet aligning member having an interval larger than the sheet width when the sheet is loaded. The first sheet alignment position is such that when the sheets are aligned, the second sheet alignment position is smaller than the sheet width, and when the sheet is carried out, the interval is substantially the same as the sheet width. Third
An image forming apparatus wherein a sheet alignment position is set. 2. The sheet aligning member according to claim 1, wherein the sheet aligning member lowers the moving speed to the third sheet aligning position from the moving speed to the first sheet aligning position and the second sheet aligning position. Image forming device. 3. When the sheet aligning member starts moving from the second sheet aligning position to the third sheet aligning position, the sheet aligning member starts contacting the sheet surface, and when the sheet aligning member reaches the third sheet aligning position,
2. The image forming apparatus according to claim 1, further comprising a delivery roller for carrying out the sheet.