JP3444699B2 - Image forming device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention automatically removes a bundle of sheets set in a non-sheet feeding position in the same sheet feeding tray when a bundle of sheets set in a sheet feeding position in a sheet feeding tray runs out. The present invention relates to an image forming apparatus such as a copying machine or a printer having a tandem sheet feeding type automatic sheet feeding unit that moves a sheet to a sheet feeding position and continuously feeds the sheet.

[0002]

2. Description of the Related Art Conventionally, when all of the sheets set at the sheet feeding position and the sheet non-feeding side in one sheet feeding tray are not fed, the sheet is not fed. An example of an image forming apparatus provided with an automatic paper feeding unit of a tandem paper feeding system for automatically moving a bundle of papers set at a position to a paper feeding position and continuously feeding the paper is disclosed in, for example, Japanese Patent Laid-Open No. 6-1.
Some are disclosed in Japanese Patent No. 44600.

This image forming apparatus has a first sheet feeding position.
And a second sheet storage section, which is a non-feeding position, are horizontally arranged side by side, and the sheets in the second sheet storage section are collectively transferred to the first sheet storage section. When the transfer unit is provided and all the sheets in the first sheet storage unit are fed during the image formation, when the sheet bundle is stored in the second sheet storage unit, the sheet transfer unit transfers the sheet bundle. Are collectively transferred to the first paper storage unit. Therefore, the paper feed is automatically restarted by the transferred paper, and the image forming operation is continued.

[0004]

However, even if such an automatic sheet feeder of the tandem sheet feeding system is provided,
After all the papers on the paper feed side that are set at the paper feed position and non-paper feed position in one paper feed tray are all gone, the bundle of papers set at the non-paper feed position is transferred to the paper feed position. It takes, for example, about 10 seconds before the sheet is fed again. Then, while the bundle of sheets is being transported, the paper feeding is stopped and the image forming operation is stopped, so the time during that time is wasted, and the number of image forming processings that can be processed per unit time is There is a problem in that the image forming operation is inefficient because it is reduced by the amount of time during which the image forming operation is stopped.

If the paper feed tray is of a type that can be pulled out from the main body of the apparatus, the user may mistakenly make a mistake in the paper feed tray while the paper is being transported in the paper feed tray. If you pull out the paper, there is a risk of jams and misalignment of the paper.

Therefore, in the image forming apparatus having such a tandem sheet feeding type automatic sheet feeding unit, it is said that "the sheet is moving" while the bundle of sheets is being transferred in the sheet feeding tray, for example. I am trying to display it on the operation panel. However, when the user overlooks this warning display or when he is in a hurry, he / she does not carefully look at the warning display and determines that the image forming operation has stopped without permission, and pulls out the paper feed tray from the main body of the device. I was afraid I might get lost.

The present invention has been made in view of the above problems, and is for a sheet feeding position side of a bundle of sheets set at a sheet feeding position and a non-sheet feeding position in one sheet feeding tray. The purpose of the present invention is to enable efficient image formation by continuing the image forming operation even while the stack of sheets set in the non-paper feed position is being transported to the paper feed position after all To do. It is also an object to prevent jamming and sheet misalignment while sheets are being transported in the paper feed tray.

[0008]

In order to achieve the above-mentioned object, the present invention can set a bundle of sheets of the same size at a sheet feeding position and a non-sheet feeding position of one sheet feeding tray, respectively. If there is no more paper set in the paper feed position during the paper feed operation, the stack of paper set in the non-paper feed position is automatically moved to the paper feed position to continue feeding paper. In an image forming apparatus equipped with an automatic paper feed unit, a stack of paper set in the non-paper feed position is automatically moved to the paper feed position after the paper set in the paper feed position is exhausted, and paper feed is resumed. Until that time, if there is a paper tray that contains paper of the same size as the paper being fed in another paper feed tray, the paper feed tray of that paper feed tray will be given priority. It was made to be performed.

[0009] In this way, when paper is being fed using the tandem paper feed type automatic paper feed unit, if all the paper set at that paper feed position is exhausted, it is set at the non-paper feed position. A stack of paper is automatically transferred to the paper feed position, but if there is a paper feed tray that contains paper of the same size as the paper being fed at that time in another paper feed stage, Until the paper feed is restarted after the transfer of the bundle of papers is completed in the paper feed unit, the paper feed tray containing the same size paper is preferentially fed, so The feeding operation is not stopped even during transfer.

In the image forming apparatus, the tandem paper feed type automatic paper feed unit may be arranged in the uppermost paper feed stage. By doing so, even if there is a paper feed tray that contains paper of the same size as the automatic paper feed unit in each paper feed tray below the automatic paper feed unit, the automatic paper feed unit will start from that paper feed tray. Since the paper is fed from the non-paper feeding position to the paper feeding position only for a short time, a large amount of paper is fed in the highest automatic paper feeding unit, so the highest paper feeding is performed. Since it suffices to replenish the paper feed tray of the automatic paper feed unit located at the position, the paper replenishment can be performed without bending the waist significantly at the time of replenishing the paper, which improves the operability.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view showing an image forming apparatus together with a control system for explaining an embodiment of the present invention, and FIG. 2 is a schematic view showing a tandem sheet feeding type automatic sheet feeding section also provided in the image forming apparatus. It is a block diagram.
The copying machine, which is the image forming apparatus shown in FIG. 1, is provided with a machine base 10 at the bottom of the apparatus body 1 having four paper feed stages 11 to 14 in the vertical direction.

The uppermost paper feed stage 11 is the first paper storage unit 2 which is the paper feed position of one paper feed tray 21.
5 and the second sheet storage portion 26, which is the non-feeding position, can set a bundle of sheets of the same size side by side along the sheet feeding direction, and are set to the sheet feeding position side during the sheet feeding operation. When the sheets P run out, the stack of sheets P set in the non-feeding position is automatically moved (transferred) to the right feeding position in FIG. It is the paper feed section.

Each of the paper feed stages 12 to 1 below the paper feed stage 11
Reference numeral 4 denotes an ordinary paper feeding unit for setting a bundle of paper P in each of the paper feeding trays (paper feeding cassettes) 22 to 24, and each of the paper feeding trays 22 to 24 has a substantially length in the paper feeding direction. They are the same, and they can be individually pulled out to the front side in FIG. 1 orthogonal to the paper feeding direction with respect to the machine base 10.

Each of the paper feed stages 12 to 14 has a pickup roller 37 and separation rollers 38, 3 shown in FIG.
The pick-up roller and the separating roller similar to those of No. 9 are provided. Each of the paper feed trays 22 to 24 of each of the second and subsequent paper feed trays 12 to 14 shown in FIG. 1 has a size detection plate 17 having a different shape corresponding to the size of the paper P stored therein. -19 (actually attached to the back of each paper feed tray, but in FIG. 1 is shown on the left side of each tray for convenience of illustration),
Paper size detection sensors 27 to 29 are provided on the machine base 10 side in correspondence with the size detection plates 17 to 19, respectively.

Therefore, when each of the paper feed trays 22 to 24 is inserted into a predetermined position of the machine base 10, the paper size detection sensors 27 to 29 detect the size detection plates 17 to 19, respectively, so that each paper feed stage is detected. The size of the paper P stored in each of the paper feed trays 22 to 24 can be understood.

When the paper P is fed one by one from the selected paper feed tray of either the paper feed trays 22 to 24 or the first paper storage section 25 of the paper feed tray 11, the paper P is fed. It is conveyed upward through the common vertical conveyance path 30 and is conveyed into the apparatus main body 1, where the photoconductor 2, the charger 3, the developing device 4, the transfer
The image is sent to the image forming unit provided with the separating device 5, the cleaning device 8 and the like.

The surface of the photoconductor 2 is uniformly charged by the charger 3, and the reflected light from the original set on the contact glass 7 is incident on the photoconductor 2 by the optical system 6 to expose the charging surface. An electrostatic latent image is formed there. The electrostatic latent image is developed with the toner supplied by the developing sleeve of the developing device 4 to form a toner image (visible image).

The toner image is temporarily stopped by the pair of registration rollers 9 and the paper is fed with timing adjusted.
To the upper surface side in FIG. 1 by the transfer / separation device 5. The paper P is separated from the photoconductor 2 and is fixed to the fixing device 3
Then, the toner is fixed there, and then discharged from a discharge port 15 outside the apparatus to a discharge tray or the like (not shown).

Then, the residual toner remaining on the photoconductor 2 after the completion of the transfer and foreign matters such as paper dust are removed by a cleaning blade provided in the cleaning device 8, and the residual potential left on the photoconductor 2 is removed. It is removed by a static elimination lamp (not shown) to prepare for the next charging by the charger 3. Note that reference numeral 16 in FIG. 1 denotes a double-sided device used when images are formed on both the front and back sides of the paper. Also, 20 is
This is an automatic document feeder that automatically feeds documents one by one onto the contact glass 7.

Next, the tandem paper feed type automatic paper feed section provided in the paper feed stage 11 will be described in detail. Figure 2
As shown in FIG. 3, the uppermost paper feed stage 11 is composed of a first paper storage unit 25 and a second paper storage unit 26, each of which is an independent paper feed tray. First
The paper storage unit 25 is supported by slide rails 33 and 34 and can be pulled out to the front side in FIG. 2 which is orthogonal to the paper P feeding direction. The second paper storage unit 26 is supported by slide rails 35 and 36, and can be pulled out to the front side in FIG. 2 which is orthogonal to the paper feed direction of the paper P, like the first paper storage unit 25. Has become.

The first sheet storage section 25 includes a first bottom plate 40.
Is rotatably provided from the position shown by the solid line in FIG. 2 to the position shown by the phantom line.
Pushed up by 3. The pressure arm 43 is rotated from a position shown by a solid line in FIG. 2 to a position shown by an imaginary line by rotating a pressure shaft 44 fixed at one end by a bottom plate lifting device using a motor or the like. To be done.

A pickup roller 37, which is rotatable in the direction of arrow A, is provided in the sheet delivery section of the first sheet storage section 25.
And a separating roller 38, 39 which is rotatable while being pressed against each other in the vertical direction. Therefore, when the pressure shaft 44 is rotated counterclockwise in FIG. 2 with the sheet P placed on the first bottom plate 40, the pressure arm 43 lifts the first bottom plate 40 from below. The topmost sheet of the paper P placed on it is pressed against the pickup roller 37.

Therefore, by rotating the pickup roller 37 in the direction of the arrow A, the uppermost sheet P is sent out from the first sheet storage section 25, and is separated into one sheet by the separation rollers 38 and 39 and fed. To be done. In the first sheet storage portion 25, a pair of mutually approaching / closing edges that regulate the positions of both side edges and the trailing edge of the sheet P placed on the first bottom plate 40.
Movable end fences 52, 5 that can be opened and closed in the separating direction
3 is provided.

A paper end detection sensor 41 for detecting the presence / absence of a sheet in the first sheet storage section 25 is arranged in the sheet delivery section of the first sheet storage section 25, and thereby, the paper end detection sensor 41 is provided. The presence or absence of the paper P in the first paper storage unit 25 is detected. The second sheet storage unit 26 has a second bottom plate 48.
A pair of fixed side fences 58 and 59 (see FIG. 3 because illustration is omitted in FIG. 2) that regulates the positions of both side edges of the sheet of paper P set above, and the position of the trailing edge of the sheet of paper is regulated. And a back fence 47 that operates.

The back fence 47 has a second bottom plate 48.
This is for pressing the substantially central portion of the paper P set above in the paper width direction and transferring it all at once to the first paper storage portion 25, and a slider 49 is attached to the lower portion thereof. The slider 49 is guided by a fence guide 45 fixed below the second bottom plate 48 in the paper feeding direction (left and right direction in FIG. 2) to move.

The slider 49 is fixed to a timing belt 51 stretched between a plurality of pulleys and rotated by the DC motor 32 in both forward and reverse directions. Use 2 to move left and right. A protruding piece 49a is formed on the slider 49, and a detection sensor 54, which is, for example, a transmissive photosensor, is provided at a position where the protruding piece 49a can be detected, and the detection sensor 54 detects the protruding piece 49a. Is the home position of the back fence 47 (the position shown in FIG. 2).

The back fence 47 has a protruding piece 49a.
2 from the home position detected by the detection sensor 54.
To the right, the movement of the protruding piece 49a is stopped at the sheet transfer completion position detected by the pressing detection sensor 55, and then the vehicle immediately retreats and the protruding piece 49a is detected again by the detection sensor 54. Return to the position.
A sheet detection sensor 61 for detecting the presence or absence of the sheet P on the second bottom plate 48 is disposed in the second sheet storage section 26.

As shown in FIG. 3, the second sheet storage section 26 is provided.
Flexible elastic members 56 and 57 for positioning the leading edge of the sheet are fixed to the pair of side fences 58 and 59 at the ends on the first sheet storage section 25 side, respectively. When the back fence 47 is pushed out by moving the back fence 47 in the direction of arrow B from the position shown in FIG. 3, the elastic members 56 and 57 are elastically deformed as shown in FIG. The movement of the bundle of sheets P in the arrow B direction is permitted.

By the way, as shown in FIG. 1, this copying machine has a bundle of sheets P set in the second sheet storage section 26 after all the sheets P set in the first sheet storage section 25 are exhausted. Is moved to a paper feed position where the pickup roller 37 is located and paper feed is resumed, a paper feed tray in which the paper of the same size as the paper being fed is stored in another paper feed tray 12 to 14 has a control device 50 for feeding paper preferentially from the paper feed tray of the paper feed stage.

The control device 50 includes a central processing unit (CPU) having various judgment and processing functions, a ROM storing each processing program and fixed data, a RAM serving as a data memory for storing the processing data, and an input / output. Circuit (I /
O) and a microcomputer. The control device 50 is housed in each of the paper feed trays 22 to 24 from the paper size detection sensors 27 to 29 arranged on the machine base 10 side corresponding to each of the paper feed stages 12 to 14, respectively. A paper size signal corresponding to the size of the paper P is input, and a paper out signal (ON signal) output from the paper end detection sensor 41 when all the paper P in the first paper storage unit 25 is exhausted is input. To do.

Further, from other sensors such as the paper detection sensor 61 described with reference to FIG.
A sheet detection signal (on / off signal) for detecting the presence / absence of the sheet, and a signal (on / off signal) for detecting the position of the back fence 47 from the detection sensor 54 and the pressing detection sensor 55. Input at the timing.

Then, a drive signal for rotating the back fence 47 is transmitted to the DC motor 32 for moving the back fence 47,
A paper feed signal for controlling the paper feed operation is output to the paper feed system of each of the paper feed stages 11 to 14 at a predetermined timing, and a predetermined load is output to various loads such as other image forming units. It outputs various drive signals for driving at timing.

FIG. 5 is a flow chart showing a routine relating to the tandem paper feeding process performed by the microcomputer of the control device 50. The microcomputer of the control device 50 starts the tandem paper feeding process routine shown in FIG. 5 at a predetermined timing. First, in step 1, it is determined whether or not the paper end detection sensor 41 is turned on to determine whether or not the paper end detection sensor 41 is turned on. It is determined whether or not all the sheets have been fed. Then, if the paper end detection sensor 41 is not turned on and there is still paper remaining, there is no need to perform tandem paper feeding, and the process returns to the main routine.

If the paper end detection sensor 41 is turned on and all the sheets are fed, the process proceeds to step 2 and the second sheet is detected depending on whether the sheet detection sensor 61 is turned on. It is determined whether or not paper is set in the storage section 26. If the paper detection sensor 61 is not on and the paper is not set, the tandem paper feed cannot be performed. Therefore, in step 3, the paper shortage display is displayed on the display unit on the operation panel and then the process returns to the main routine. .

If the paper detection sensor 61 is turned on in step 2 and the process proceeds to step 4, the DC motor 32 shown in FIG. The back fence 47 is moved to the right in the figure. And, almost at the same time, next step 5
Then, it is determined whether or not there is a paper feed tray in which the paper of the same size as the paper fed in the first paper tray 25 is stored in the other paper feed trays 12 to 14.

If not, the process proceeds to step 6 to judge whether or not the pressing detection sensor 55 of FIG. 2 is turned on, and if it is not turned on yet, the back fence 47.
Is transferring the bundle of sheets P set in the second sheet storage section 26 to the first sheet storage section 25, so wait as it is, and if the pressing detection sensor 55 is turned on, proceed to step 7. Then, the paper feed from the first paper storage unit 25 of the tandem paper feed type automatic paper feed unit is restarted, and then the process returns to the main routine.

On the other hand, in step 5, the other paper feed stage 1
When there is a paper feed tray containing paper of the same size as the paper fed in the first paper storage portion 25 in 2 to 14, the process proceeds to step 8 and the paper feed operation from the paper feed tray is performed. To start. Next, in step 9, as in step 6, it is determined whether or not the pressing detection sensor 55 is turned on, and if it is not turned on, wait until it is turned on, and when it is turned on, the second paper storage unit is turned on. Since the transfer of the bundle of sheets set in 26 to the first sheet storage unit 25 is completed, the process proceeds to step 10.

Therefore, the DC motor 32 is reversely rotated until the back fence 47 described in FIG. 2 returns to the home position, and in the next step 11, the paper is transferred from the second paper storage unit 26 to the first paper storage unit 25. The paper feeding operation from the other paper feeding stage that was feeding the paper during the transportation of the paper is stopped. And
In the next step 7, paper feed from the first paper storage unit 25 of the tandem paper feed type automatic paper feed unit is restarted, and then the process returns to the main routine. When the paper end detection sensor 41 detects the absence of paper when the bundle of papers set in the second paper storage unit 26 is transferred to the first paper storage unit 25 by the tandem paper feeding, FIG. 6A
First, the first bottom plate 40 is lowered, and the movable end fences 52 and 53 (see FIG. 2) are opened, as shown in FIG.

Next, as shown in FIG. 6B, the bundle of sheets P in the second sheet storage section 26 is changed to the first sheet storage section 25.
Start the transfer to. Then, as shown in (c) of FIG. 6, when the transfer of the paper P is completed, the back fence 47 immediately returns to the home position shown in (a) of FIG. 6, and the movable end fences 52, 53 (FIG. 2) closes.
Then, the first bottom plate 40 rises, and the sheet feeding operation starts again.
During this period, the paper feeding is stopped in the paper feeding stage 11, and the time is about 10 seconds.

In this embodiment, as is clear from FIG. 1, the paper feed tray 11 having the tandem paper feed type automatic paper feed portion is arranged at the uppermost paper feed tray. Therefore, even if each of the lower paper feed trays 12 to 14 has a paper feed tray in which sheets of the same size as the paper feed tray 11 are stored, the number of papers fed from the paper feed tray is It is only for a short time when the paper P is transferred to the first paper storage unit 25 at 11, for example, it is less than 10 in a copying machine that makes 50 copies per minute. Therefore, a large amount of paper is consumed in the uppermost paper feed stage 11, so that the first paper storage unit 25 and the second paper storage unit 26 at the higher position are consumed.
Since it suffices to replenish the paper, it is possible to replenish the paper easily because the waist does not have to be bent greatly when replenishing the paper.

[0041]

As described above, according to the present invention, there is no sheet set at the sheet feeding position during the sheet feeding operation in the tandem sheet feeding type automatic sheet feeding unit, and the sheet is set at the non-sheet feeding position. While another stack of paper is automatically moved to the paper feed position, if another paper feed tray has a paper tray that contains paper of the same size as the paper being fed, Since the paper feeding operation is continued without being interrupted by the paper feeding from the paper feeding tray of the paper feeding stage, the productivity of image formation is enhanced. Also, while the paper is being transferred in the tandem paper feed system, the paper is not stopped and paper is fed from the other paper feed tray, so the user may accidentally Since there is no need to pull out the paper feed tray, it is possible to prevent jams and misalignment of paper that occur when the paper feed tray is operated during paper feeding.

Furthermore, if the above-mentioned tandem paper feed type automatic paper feed unit is arranged in the uppermost paper feed stage, an automatic paper feed unit is provided in each paper feed stage below the automatic paper feed unit. Even if there is a paper feed tray that contains paper of the same size, paper is fed from that paper feed tray for a short time while the automatic paper feeder moves the paper from the non-paper feed position to the paper feed position. Since only the uppermost automatic paper feed unit is supplied with a large amount of paper, it is only necessary to add paper to the paper feed tray of the automatic paper feed unit at a higher position. Sometimes paper can be supplied without bending the waist significantly, improving operability.

[Brief description of drawings]

FIG. 1 is a schematic view showing an image forming apparatus and a control system for explaining an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing an automatic sheet feeding unit of a tandem sheet feeding method, which is also provided in the image forming apparatus.

FIG. 3 is a perspective view showing a pair of side fences similarly provided in a second sheet storage section of the automatic sheet feeding section and a pair of elastic members each having one end fixed thereto.

FIG. 4 is a plan view showing a state where the elastic member elastically deforms to allow movement of a bundle of sheets P pushed out.

5 is a flowchart showing a routine relating to a tandem paper feeding process performed by a microcomputer of the control device 50 of FIG.

6A and 6B are schematic diagrams showing stepwise a tandem sheet feeding process performed in a sheet feeding stage 11 of the image forming apparatus of FIG.

[Explanation of symbols]

11-14: Paper feed stage 21-24: Paper feed tray 25: First paper storage unit (paper feed position) 26: Second paper storage unit (non-paper feeding position) 32: DC motor 47: Back fence 50: Control device 51: Timing belt

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B65H 1/30 320 B65H 3/44 342 G03G 15/00 516

Claims (2)

(57) [Claims] 1. A sheet bundle of the same size can be set in a sheet feeding position and a non-sheet feeding position of one sheet feeding tray, and the sheets set in the sheet feeding position disappear during the sheet feeding operation. And an image forming apparatus including a tandem automatic feeding unit for automatically moving a bundle of sheets set in the non-feeding position to the feeding position and continuing feeding. A stack of paper set in the non-paper feed position will automatically be placed in the paper feed position after the paper set in the paper feed position is exhausted.
If there is a paper feed tray that contains paper of the same size as the paper that was being fed in another paper feed tray until the paper is dynamically moved and paper feed is restarted, An image forming apparatus characterized in that a sheet is fed preferentially from a sheet feeding tray. 2. The image forming apparatus according to claim 1,
An image forming apparatus, wherein the tandem paper feed type automatic paper feed unit is arranged in the uppermost paper feed stage.