JPH11208965A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device preventing a void recording sheet from being included in a sheet arranging tray by discharging the void recording sheet to a discharge tray in the case of the generation of the void recording sheet during a recording sheet adjusting process using the sheet arranging tray, and preventing the generation of a recording sheet jam at a gate part for selecting the discharge tray of the sheet arranging tray. SOLUTION: In the case of a recording sheet P being proved to be a void recording sheet during execution of processing for storing the recording sheet P having passed an image forming part 11, in a sheet arranging tray 23, a switching gate 31 is driven on the basis of whether or not the tip of the void recording sheet has reached the switching gate 31, and the void recording sheet is discharged to the sheet arranging tray 23 or a discharge tray 26.

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 an electrophotographic copying machine or a printer, and more particularly, to forming a predetermined sheet bundle by aligning recording sheets on which an image has been formed. If so, the present invention relates to an image forming apparatus capable of performing various post-processing such as stapling processing on the sheet bundle.

[0002]

2. Description of the Related Art JP-A-1-259375 and JP-A-6-32442 disclose that a recording sheet on which a recording image has been formed is aligned with a predetermined sheet bundle, and that the sheet bundle is stapled. An image forming apparatus capable of performing various post-processing such as ring processing is disclosed. In the image forming apparatuses disclosed in these publications, after forming a recorded image on a recording sheet in an image forming unit having a photosensitive drum,
The recording sheets sequentially discharged from the image forming section are temporarily stored in a sheet aligning tray, the recording sheets are aligned in a page order to form a sheet bundle, and the sheet bundle for which page alignment has been completed is transferred from the sheet aligning tray to the stacker tray. It is configured to discharge and stack. In addition, a stapler is provided in the sheet alignment tray, so that a stapling process can be performed on a sheet bundle on which pages have been aligned as necessary.

On the other hand, some recording sheets that have passed through the image forming section do not require alignment processing. Therefore, a discharge tray for accommodating such recording sheets is provided separately from the sheet alignment tray. The recording sheet that has passed through the image forming unit is selectively discharged to a discharge tray or a sheet alignment tray by a switching gate.

In a copying machine or the like, if an original feeding error occurs during a copying operation using, for example, an automatic document feeder (ADF), the copying machine automatically stops the copying operation. A recording sheet whose image forming operation has not been completed normally (hereinafter, invalid recording sheet) will remain in the sheet conveyance path in the copying machine. Particularly, in a high-speed copying machine in which the number of copies per unit time is large, several invalid recording sheets are generated, and when restarting the copying operation, all parts of the housing of the copying machine are opened and all invalid recording sheets are opened. Must be removed from the copying machine.

Therefore, in a recent copying machine, in order to make it easier to restart the copying operation, a so-called purge process for automatically discharging the invalid recording sheet out of the copying machine and restarting the copying operation. Has been adopted. In particular, in the image forming apparatus having both the sheet alignment tray and the discharge tray, when an invalid recording sheet is generated during the execution of the alignment process using the sheet alignment tray, the invalid recording is performed by driving the switching gate. A measure is taken to selectively discharge only the sheets to the discharge tray and prevent the invalid recording sheets from being mixed in the sheet alignment tray.

[0006]

However, in recent years, the size and space of the image forming apparatus have been reduced, and of course, the conveying path of the recording sheet from the image forming section to the switching gate has also been shortened. It is becoming.
For this reason, for example, when an invalid recording sheet occurs due to an abnormal writing of an electrostatic latent image on the photosensitive drum or the like,
Although the recording image is still formed near the trailing edge of the recording sheet, a situation may occur in which the leading edge of the recording sheet has already passed through the switching gate toward the sheet alignment tray.

Accordingly, in such a situation, the switching gate is driven every time an invalid recording sheet is generated, as in the related art,
If the process of uniformly discharging the invalid recording sheet to the discharge tray is performed, a jam of the recording sheet occurs at the switching gate, and the invalid recording sheet is automatically discharged out of the image forming apparatus. Is lost.

The present invention has been made in view of such a problem, and an object of the present invention is to perform such recording when an invalid recording sheet occurs during the alignment processing of recording sheets using a sheet alignment tray. Sheets are ejected to the output tray as much as possible to prevent invalid recording sheets from being mixed in the sheet alignment tray, while preventing the recording sheet from jamming at the gate for selecting the output tray and sheet alignment tray. It is an object of the present invention to provide an image forming apparatus capable of preventing as much as possible.

[0009]

In order to achieve the above object, an image forming apparatus according to the present invention comprises: an image forming section for forming a recording image corresponding to image information on a recording sheet; And a sheet aligning tray for selectively stapling the aligned sheet bundle. The sheet aligning tray is provided separately from the sheet aligning tray. A discharge tray accommodating the passed recording sheets, and a switching gate for selectively guiding the recording sheets passed through the image forming unit to the sheet aligning tray or the discharging tray, wherein a distance from the image forming unit to the switching gate is reduced. Assuming that the image forming apparatus is set to be shorter than the maximum size of the recording sheet that can be handled, the recording sheet that has passed through the image forming unit is used as the sheet. If the recording sheet is determined to be an invalid recording sheet before the leading end of the recording sheet reaches the switching gate during the process of storing the sheet in the alignment tray, the switching gate is driven. While the recording sheet is guided to the discharge tray, if the recording sheet is determined to be an invalid recording sheet after the leading end of the recording sheet has passed through the switching gate, the switching gate is driven. And the recording sheet is discharged to the sheet alignment tray.

According to such technical means, when the invalid recording sheet is generated in the image forming section, the position of the leading end of the invalid recording sheet is used as a reference, and the leading end of the invalid recording sheet is switched to the switching gate. If it is located in front, the switching gate is driven to discharge the invalid recording sheet to the discharge tray, while if it has already passed the switching gate, without driving the switching gate, Since the invalid recording sheet is discharged to the sheet alignment tray as it is, excessive switching gate drive during the recording sheet passage is prevented, and invalid recording sheets are generated and the invalid recording sheets are jammed at the switching gate. The occurrence of multiple troubles can be prevented.

Therefore, in the present invention, the invalid recording sheet may be discharged to the sheet aligning tray without being discharged to the discharge tray. It is assumed that they are mixed in the alignment tray. Therefore, if the invalid recording sheet is unavoidably discharged to the sheet alignment tray, it is preferable to prohibit the stapling process on the sheet bundle aligned by the sheet alignment tray.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image forming apparatus according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows an embodiment of the image forming apparatus of the present invention. In the figure, reference numeral 10 denotes a digital copying machine for copying image information of a document onto a recording sheet, and reference numeral 20 denotes a recording sheet P discharged from the digital copying machine to be aligned with a predetermined number of sheet bundles. 4 shows a finisher that performs stapling processing on a sheet bundle.

The digital copying machine 10 includes a photosensitive drum 1
The photosensitive drum 11 is exposed with a laser beam Bm modulated according to image information to form an electrostatic latent image, and the electrostatic latent image is developed by a developing unit (not shown). It is configured to form a toner image on the body drum 11. On the other hand, the recording sheet P on which the toner image is transferred is fed from a paper feed tray (not shown), and hits a gate 12 disposed on the front side of the photosensitive drum 11 so that the conveyance skew is corrected. Has become. When the gate 12 is opened at a predetermined timing synchronized with the writing timing of the electrostatic latent image, the recording sheet P
Is transferred to the toner image transfer point by the registration roll 13, and the toner image is transferred from the photosensitive drum 11 to the recording sheet P.

The recording sheet P on which the toner image has been transferred in this manner is inserted into a fixing device 14, and after the fixing of the toner image onto the recording sheet P is completed, the finisher is moved from the copying machine 10 through an exit roll 15 to the finisher. It is discharged to the 20 side.
A sheet detection sensor 16 is provided near the exit roll of the copier. By checking an output signal of the sheet detection sensor 16, it is determined whether or not the recording sheet P has been correctly discharged to the finisher 20 side. Can be confirmed.

FIG. 2 shows a specific configuration of the finisher. In the figure, reference numeral 21 denotes a housing of the finisher 20. A sheet discharge port 22 communicating with the inside of the housing 21 is formed on a side of the housing 21 opposite to the copying machine body 10.
Inside, a fixed tray 24 which is a part of the sheet alignment tray 23 is disposed. A stacker tray 25 is disposed below the opening 22 so as to be vertically movable, and is configured to receive a sheet bundle discharged from the sheet alignment tray 23. On the other hand, the sheet discharge port 22
A non-finishing tray 26 is fixedly arranged above the recording sheet P, and the recording sheets P that do not require the stabilizing process and the aligning process are discharged to the non-finishing tray 26.

A sheet introduction port 27 is opened in the housing 21 corresponding to the sheet discharge port 17 of the copying machine 10, and a recording sheet P introduced from the sheet introduction port 27 is transferred to a sheet via a sheet transport system 28. The sheet is conveyed to either the alignment tray 23 or the non-finishing tray 26. The sheet transport system 28 includes a first sheet transport path 29 leading to the sheet alignment tray 23.
And a second sheet transport path 30 communicating with the non-finishing tray 26, and one of the sheet transport paths is switched and selected by a switching gate 31 disposed near the sheet inlet 27.

On the other hand, above the fixed tray 24, a first
A sheet conveying roll 32 for sending out the recording sheet P conveyed through the sheet conveying path 29 to the sheet discharge port 22 is provided. The recording sheet P sent out by the sheet conveying roll 32 is provided. A part of which protrudes out of the housing 21 from the sheet discharge port 22,
The fixed tray 24 and the stacker tray 25 are accommodated so as to be straddled. The fixed tray 2
A paddle wheel 33 for rubbing the recording sheet P toward the lower edge of the fixed tray 24 is disposed on the upper side of the fixed sheet 24, and tampers 34 for aligning the side edges of the recording sheet P are disposed on both sides thereof. The operation of the paddle wheel 33 and the tamper 34 aligns the recording sheets P stacked on the sheet alignment tray 23 to form a predetermined sheet bundle.

Further, a stapler 35 is provided at a lower end edge of the fixed tray 24, and selectively performs a stapling process on an edge portion of the sheet bundle aligned at a predetermined position on the fixed tray 24. It is configured as follows.

Further, a pair of discharge rolls 36 and a support roll 37 are disposed inside the sheet discharge port 22 with the fixed tray 24 interposed therebetween. The sheet bundle is discharged to the stacker tray 25. Also,
The discharge roll 36 is configured to be able to retract from above the fixed tray 24 by swinging of the arm 38 so as not to hinder the discharge operation of the recording sheet P to the fixed tray 24. The fixed tray 24 is set on
It is configured to sandwich the upper sheet bundle.

In the image forming apparatus of the present invention configured as described above, when a user inputs a copying operation using the non-finishing tray 26 or the sheet aligning tray 23 from the operation unit of the copying machine 10, the copying operation is performed according to the input contents. When the switching gate 31 of the finisher 20 is driven and the copying operation is started, the recording sheet P on which the toner image has been fixed is discharged to one of the selected trays.

In this image forming apparatus, when a document feeding jam occurs in an automatic document feeder (not shown) or an abnormality occurs in image processing of a read document, the operation of the copying machine 10 is stopped. Without doing
A so-called purge process is automatically performed in which the recording sheet P fed from the paper feed tray into the copying machine 10 and the transfer of the toner image has not been normally completed is discharged out of the copying machine 10 as an invalid recording sheet. ing.

When an invalid recording sheet is generated during the copying operation in which the non-finishing tray 26 is selected, the invalid recording sheet is also discharged to the non-finishing tray 26 like the valid recording sheet. Since the alignment process of the recording sheet P is not performed, no problem occurs even if the purge process is directly executed. However, if an invalid recording sheet is generated during the copying operation in which the sheet alignment tray 23 is selected, the sheet bundle alignment process is performed in a state where the invalid recording sheet is mixed with the valid recording sheet. Since the stapling process may be performed as it is, there is a problem in executing the purge process as it is.

Therefore, in the image forming apparatus of this embodiment, if an invalid recording sheet is generated during the copying operation in which the sheet aligning tray 23 is selected, the switching gate 31 of the finisher 20 is driven to drive the toner image. Only the effective recording sheet for which the transfer has been completed normally is placed in the sheet alignment tray 2
In addition, the invalid recording sheet on which the toner image could not be transferred normally is discharged to the non-finishing tray 26 while the toner image is not normally transferred, and the effective recording sheet and the invalid recording sheet are prevented from being mixed on the sheet alignment tray 23 as much as possible. Like that.

However, when the occurrence of an invalid recording sheet is determined, the leading end of the invalid recording sheet is already switched to the switching gate 31.
When the switching gate 31 is forcibly driven, a jam of the recording sheet P occurs, and in such a case, the switching gate 31
The invalid recording sheet is discharged to the sheet aligning tray 23 without driving the sheet. However, since complicated timing control is required to accurately determine whether the leading end of the invalid recording sheet has reached the switching gate 31, in this embodiment, the sheet discharge port 1 of the copying machine 10 is used.
The signal from the sheet detection sensor 16 disposed in the printer 7 is checked to determine whether or not to drive the switching gate 31 according to whether or not the leading end of the invalid recording sheet has been introduced from the copying machine 10 to the finisher 20. I have decided.

In such a case, for example, as shown in FIG.
The sum of the circumference X from the m exposure point to the transfer point of the toner image and the distance Y from the transfer point to the sheet detection sensor 16, that is, (X + Y) is the maximum size of the recording sheet P that can be handled by the copying machine 10. Occurs when the length is shorter than the length. That is, in such a case, even though the leading edge of the recording sheet P has already reached the sheet detection sensor 16, the writing of the electrostatic latent image corresponding to the trailing edge of the recording sheet P on the photosensitive drum 11 is performed. If the electrostatic latent image corresponding to the original image cannot be formed accurately due to the image processing abnormality, the recording sheet P
Becomes an invalid recording sheet, and the switching gate 31
This is because there is no time to drive the invalid recording sheet to the non-finishing tray 26 by driving the.

FIG. 3 is a flowchart showing a specific procedure of the purge process during the copying operation in which the stapling process by the sheet alignment tray 23 is selected. First, when it is determined that an invalid recording sheet has occurred in the copying machine (ST1), the output of the sheet detection sensor 16 located at the sheet discharge port 17 of the copying machine is checked.
It is checked whether the leading end of the invalid recording sheet has been inserted into the finisher 20 (ST2). Here, if the sheet detection sensor 16 does not detect the leading edge of the recording sheet P, it means that the leading edge of the invalid recording sheet has not reached the switching gate 31 of the finisher 20, and in this case, switching is performed immediately. Gate 31
Is driven (ST3) to switch the discharge destination of the recording sheet P introduced into the finisher 20 from the sheet alignment tray 23 to the non-finishing tray 26. As a result, the invalid recording sheet generated in the copying machine is guided to the non-finishing tray 26. When it is confirmed that all the invalid recording sheets have been discharged to the tray 26 (ST4), the purging process is terminated (ST4). ST5), the copying machine resumes the remaining copying work.

On the other hand, if the sheet detection sensor 16 has already detected the leading edge of the recording sheet P in ST2, there is a possibility that the leading edge of the invalid recording sheet has already passed through the switching gate 31. Since it is impossible to discharge the invalid recording sheet to the non-finishing tray 26, the invalid recording sheet is directly driven without driving the switching gate 31.
To be discharged. Then, it is checked whether or not the stapling process is selected in this copying operation (ST
5) If selected, the stapling process is forcibly canceled in order to avoid performing the stapling process while the invalid recording sheet and the valid recording sheet are mixed in the sheet alignment tray (ST6). ).

Thereafter, it is checked whether or not the ejection of all invalid recording sheets to the sheet aligning tray 23 has been completed (ST7). If it is determined that the discharging has been completed, the alignment of the sheet bundle in the sheet aligning tray 23 is performed. It is checked whether or not the processing has been completed (ST8). If it is determined that the sheet bundle alignment process has been completed, the sheet bundle aligned in the sheet alignment tray 23 at this time is discharged to the stacker tray 25 without waiting for the copying operation to be completed. (ST9). Next, it is checked whether or not the discharging process has been completed (ST10). If it is determined that the discharging has been completed, a message as shown in FIG. 4 is displayed on the display section of the operation panel of the copying machine 10. , Stacker tray 2
In step 5, the operator is prompted to remove the invalid recording sheet from the sheet bundle finally discharged (ST11).

This completes the purging process, and the copying machine 1
0 resumes the rest of the copying work. At this time, the recording sheets P related to the remaining copy work after the purge processing are aligned on the sheet alignment tray 23, but the recording sheets P before the purge processing are already aligned and discharged to the stacker tray 25. Therefore, by discharging the remaining recording sheets P to the stacker tray 25 as they are after the alignment processing, the recording sheets P before and after the purge processing can be completed on the stacker tray 25 into one sheet bundle.

[0030]

As described above, according to the image forming apparatus of the present invention, whether or not the leading end of the invalid recording sheet has reached the switching gate when the invalid recording sheet is generated in the image forming section. Therefore, the discharge destination of the invalid recording sheet is allocated to the sheet aligning tray or the discharge tray, so that the invalid recording sheet is prevented from being mixed with the valid recording sheet in the sheet aligning tray as much as possible. In this case, it is possible to prevent a recording sheet from being jammed as much as possible.

[Brief description of the drawings]

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

FIG. 2 is a schematic diagram showing a configuration of a finisher attached to the copying machine.

FIG. 3 is a flowchart showing a specific procedure of a purge process in the present invention.

FIG. 4 is a diagram illustrating an example of a message displayed to an operator of a copying machine in a purge process.

[Explanation of symbols]

10 photocopier, 11 photoconductor drum (image forming unit), 2
0: Finisher, 23: Sheet alignment tray, 26: Non-finishing tray (discharge tray), 31: Switching gate

Claims (2)

[Claims] An image forming section for forming a recording image corresponding to image information on a recording sheet, a recording sheet having passed through the image forming section is accommodated and aligned, and the aligned sheet bundle is A sheet aligning tray on which a stapling process is selectively performed, a discharge tray which is provided separately from the sheet aligning tray, and which stores a recording sheet also passing through the image forming unit, and a recording sheet passing through the image forming unit. A switching gate for selectively guiding to the sheet alignment tray or the discharge tray, wherein the distance from the image forming unit to the switching gate is set to be shorter than the length of the maximum size recording sheet that can be handled, During the process of storing the recording sheet that has passed through the image forming unit in the sheet alignment tray, the leading end of the recording sheet If it is determined that the recording sheet is an invalid recording sheet before reaching the switching gate, the switching gate is driven to guide the recording sheet to the discharge tray. If the recording sheet is determined to be an invalid recording sheet after passing through the switching gate, the recording sheet is discharged to the sheet alignment tray without driving the switching gate. . 2. The image forming apparatus according to claim 1, wherein
An image forming apparatus wherein when an invalid recording sheet is discharged to a sheet alignment tray, stapling processing in the sheet alignment tray is prohibited.