JPH04118668A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent useless image forming by inhibiting the switching of paper feeding in the case of detecting no paper even though another stage for feeding the paper of the same size exists. CONSTITUTION:In the case that a paper is fed from a paper feeding stage which is set by a specified paper feeding stage setting means D while an image is being formed, the switching of paper feeding by an automatic paper feeding switching means C is inhibited by a switching inhibiting means E in the case of detecting no paper in the above paper feeding stage even when another paper feeding stage where paper of the same size as the paper which is housed in the above paper feeding stage exists, so that the useless image forming by an undesirable switching to other undesired paper is prevented from occurring even though there is no paper when the special paper having different chartaceous and color from plain paper is set in the specified paper feeding stage and the paper is fed therefrom so as to form the image.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to image forming apparatuses such as various printers, copiers, facsimile machines, and the like.

[Conventional technology]

In general, in an image forming apparatus equipped with multiple paper feed stages such as a copying machine, during image formation, when paper is being fed from a selected paper feed stage of each paper feed stage, the When a paper tray is detected to be out of paper, if there is a paper tray that stores paper of the same size as the paper stored in that paper tray, the machine automatically switches to that paper tray. , some have a limitless paper feeding function so that image formation can continue as is.

[Problem to be solved by the invention]

However, in image forming apparatuses equipped with such conventional glue-less paper feeding functions, special paper that is different in quality and color from normal paper is set in one of the paper feed stages, and then the paper is fed from that paper feed stage. Even when images are being formed on paper, the paper feed tray runs out of paper and is fed manually, so the image formation process may be applied to paper of different colors or paper quality during the process. There was a problem that paper could be wasted.

On the other hand, if a special paper such as the one described above is set in one of the paper feed trays and paper is fed from a paper feed tray in which normal paper is set, and image formation is performed,
When the paper in the paper feed tray runs out, special paper may be fed by limitless paper feeding, so image formation processing is performed on paper of a different color or paper quality during the process, resulting in wasted paper. Sometimes I end up doing this.

This invention has been made in view of the above points, and a special paper that is different in quality, color, etc. from normal paper is set in one of the paper feed trays.

Even if the paper runs out when forming an image by feeding paper from that paper feed tray or another paper feed tray, the paper is switched to another undesired paper, resulting in wasted image formation. The purpose is to ensure that there are no

[Means to solve the problem]

In order to achieve the above object, the present invention includes a plurality of paper feed stages, and paper presence/absence detection means A for detecting the presence or absence of paper in each paper feed stage, as shown in the functional block diagram in FIG.
A paper size detection means B detects the size of paper stored in each paper feed tray, and when paper is being fed from a selected paper feed tray from among the plurality of paper feed trays during image formation. If it is detected that there is no paper in the paper feed tray, if there is another paper feed tray that stores paper of the same size as the paper stored in the paper feed tray, the paper will be fed from that paper feed tray. In the image forming apparatus, the image forming apparatus is equipped with an automatic paper feed switching means C that automatically switches between paper feed stages, and a specific paper feed stage setting means that sets one of the plurality of paper feed stages as a specific paper feed stage. During image formation, when paper is being fed from the paper feed cassette set by the specific paper feed cassette setting means, if no paper is detected for the paper feed cassette, the paper feed cassette is automatically Even if there is another paper feed tray that stores paper of the same size as the paper that was stored in the .

A switching inhibiting means E for inhibiting paper feeding switching by the automatic paper feeding switching means C is provided.

In addition, as shown in the functional block diagram in FIG. 2, instead of the switching prohibition means E in FIG. When paper is being fed from a tray, no paper is detected for the paper feed tray, and the specified paper feed tray stores paper of the same size as the paper that was stored in the paper feed tray. A switching permitting means F may be provided that permits the automatic paper feeding switching means C to switch the paper feeding only when there is a paper feeding stage other than the paper feeding stage.

Furthermore, as shown in the functional block diagram in FIG.

In addition to the means shown in FIG. 2, a specific document discriminating means G is provided for discriminating a specific document from among a plurality of documents used when forming an image using a document. When forming an image using a document, the specific paper feed cassette setting unit may set a predetermined paper feed cassette as the specific paper feed cassette.

[For production]

In the image forming apparatus of FIG. 1 according to the present invention, during image formation, when paper is being fed from the paper feed cassette set by the specific paper feed cassette setting means, there is no paper in the paper feed cassette. When detected, even if there is another paper feed tray storing paper of the same size as the paper stored in the paper feed tray, the switching prohibition means E prevents the paper feed automatic switching means C from feeding. Since paper switching is prohibited, if you set a special paper with a different quality or color than normal paper in a specific paper feed tray, and then feed paper from there to form an image, that paper runs out. It is also possible to prevent unnecessary image formation from being performed by switching to another undesired paper.

Further, in the image forming apparatus of FIG. 2 according to the present invention, during image formation, when paper is being fed from a paper feed cassette other than the specific paper feed cassette set by the specific paper feed cassette setting means,
Only when it is detected that there is no paper in the paper feed tray, and there is a paper feed tray other than the above-mentioned specific paper feed tray that stores paper of the same size as the paper stored in the paper feed tray,
Since the switching permission means F allows the paper feed automatic switching means C to switch the paper feed, it is possible to feed normal paper from other paper feed trays while special paper is set in a specific paper feed tray. Even if the paper runs out while performing image formation, it is possible to prevent unnecessary image formation by switching to an undesired special paper.

Note that, by combining both inventions, it is possible to provide an image forming apparatus that is more effective in layer formation.

Furthermore, in addition to the above-mentioned functions, the image forming apparatus of FIG. 3 according to the present invention has the following functions when forming an image using a document:
When the specific document discriminating means G discriminates a specific document from among the plurality of documents used, and image formation is performed using the determined specific document, the specific document feed cassette fixed means is determined in advance. Since the paper feed stage is set as a specific paper feed stage, not only can the same effect as described above be obtained, but also, for example, if the first and last originals are determined as specific originals, each original image will be displayed on thick paper, etc. This is very convenient when binding books, etc., because the copies are made on special paper.

〔Example〕

Hereinafter, embodiments of the present invention will be specifically described with reference to FIG. 4 and subsequent figures.

FIG. 4 is a schematic configuration diagram showing an example of a copying machine equipped with a plurality of paper feed trays (paper feed cassettes) embodying the present invention.

In this copying machine, when an original is set on a contact glass 1 and a copy start key is pressed, the original is exposed by an exposure lamp 2. Then, the reflected light from the original is sent to the first mirror 3. 2nd mirror 4. Third mirror5. Via the lens unit 6, the fourth mirror 7, and the dustproof glass 8.

An image is formed on the surface of the photoreceptor drum 9.

The photosensitive drum 9 is rotationally driven in the direction of the arrow by a main motor 10 via a power transmission mechanism (not shown). A first scanner composed of an exposure lamp 2, a first mirror 3, etc. is mounted on a first carriage (not shown) and is driven in the direction of arrow A at a constant speed. A second scanner comprising a second mirror 4, a third mirror 5, etc. is mounted on a second carriage (not shown) and is driven in the direction of arrow A at a speed 172 times the speed of the first carriage.

The first scanner can expose the entire surface of the contact glass 1 by moving the distance from the reference side (left end) of the contact glass 1 to the opposite side (right end) parallel to that surface at a constant speed.

The surface of the photosensitive drum 9 is uniformly charged by the charging charger 11, and the charged surface is exposed to light by the above-mentioned image formation to form an electrostatic latent image.

When the latent image passes through the eraser 38, the charges in unnecessary parts (front end, side end, rear end) are erased, and then toner is attached to the developing roller 12a of the developing unit 12 and developed. It becomes a visible image and is sent to the transfer charger 13, but before the transfer process is performed there,
In order to suppress the occurrence of retransfer during separation as described below,
Pre-transfer static elimination is performed by a pre-transfer static elimination lamp (PTL) 14 to reduce the adhesion force (charge) between the photosensitive drum 9 and the toner.

The paper is fed from one of the paper feed cassettes 15, 16, and 40° 41 to the paper feed roller 18 by the calling roller 17, and the paper feeding roller 18 and the paper feeding roller 18 located below the calling roller 17 are arranged to prevent double feeding. Only one sheet is separated and fed by the reversing rollers 19, and then reaches the registration rollers 20. At this time, the paper is conveyed again along the paper guide to the surface of the photoreceptor drum 9 facing the transfer charger 13, and the visible image on the photoreceptor drum 9 is transferred to that surface.

The recorded paper is stored in the separation charger 21 and the separation claw 2.
It is separated from the photoreceptor drum 9 by the conveyor belt 2.
3 and enters the fixing unit 24. There, after receiving heat to fix the image, it is guided by a paper guide and ejected.

On the other hand, the surface of the photosensitive drum 9 on which the transfer has been completed is neutralized by a pre-cleaning charger (PCC) 26 before being cleaned by the cleaning unit 25, and the toner remaining on the surface is removed by the fur brush 25a of the cleaning unit 25. The toner that has been scraped off but remains unremoved is removed by the cleaning blade 25b.
scraped off by Furthermore, the residual charge on the surface is eliminated by a static elimination lamp (QL) 27, in preparation for the next image forming process.

The paper ejected from the fixing unit 24 is transferred to the switching claw 2 except when transferring the paper to one side in the double-sided copy mode.
8, the paper is sent to a paper discharge roller 29 and is discharged to a paper discharge tray (not shown).

In addition, when transferring one side of the paper in the double-sided copy mode, the switching claw 28 is switched to the position shown by the imaginary line, and the paper is sent to the reversing guide 3o, so that the rear end of the paper is transferred to the contact roller 30.
When the paper comes into contact with the paper, the contact/separation roller 31 is reversed and the paper is reversely conveyed toward the intermediate tray 32 .

The paper is then discharged onto the intermediate tray 32 by one of the three gate claws 33. These three gate claws 33 are switched depending on the size of the paper being sent, only those that are suitable for that size.

The paper discharged to the intermediate tray 32 is moved to the leading end shifting roller 34
The paper is further fed to a paper stopper 35 by the roller 34 and stocked.

Thereafter, when paper is re-feeded from the intermediate tray 32, the leading end shifting roller 34 is separated from the paper and the paper stopper 35 is released, and then the paper is rotated on both sides by the rotation of the roller 36 and the double-sided paper feeding roller 37a is released. Further, only one sheet of paper is separated by the roller 37a and the double-side reversing roller 37b located below to prevent double feeding, and is re-fed toward the registration roller 20, and thereafter the same copying process as described above is performed. After the process, the other side is also copied.

Note that 39 is a photosensor (hereinafter referred to as "P sensor") used when making process corrections such as development bias, and is fixedly arranged opposite to photoreceptor drum 9, and irradiates light onto the surface of the photoreceptor drum 9. Outputs a detection signal according to the amount of reflected light.

FIG. 5 is a diagram showing a specific example of the configuration of the paper feed cassette 15 of FIG. 4 and its surroundings.

The paper feed cassette 15 is provided with a bottom plate 42 on which a plurality of sheets of paper are placed, which can be moved up and down.

A light-shielding plate (not shown) for size identification is fixed to the tip of the case 43 of the paper feed cassette 15, and a light-shielding plate (not shown) is fixed to the tip of the case 43, and the light-shielding part of the light-shielding plate is held in place to detect the installation of the cassette and the size of paper to be stored inside. A paper size detection sensor 44 using five photointerrupters is arranged, and is pivoted to the back side of the case 43 so as to be able to swing vertically by a rotating shaft 45a, and a right-handed rotational behavior is provided by a spring (not shown). A bottom plate lifting arm 45 is provided.

Further, an actuator (actuator) 48 having a light shielding plate 47 integrally formed at its rear part is pivotally mounted on the upper part of the paper feed cassette 15 by a rotary shaft 46, and the light shielding plate 47
A paper end detection sensor 49 using a photointerrupter is arranged so that the optical path is interrupted by the rise of the paper end sensor 49.

Note that the calling roller 17 is configured to rotate in the direction of the arrow together with the paper feeding roller 18 and the reversing roller 19 when the driving force from the main motor 10 is applied to the paper feeding clutch.

Here, when the paper feed cassette 15 is installed as shown in FIG.
The bottom plate 42 is placed in contact with the back surface of the bottom plate 42 through a.
lift upwards.

As a result, the uppermost paper placed on the bottom plate 42 hits the pick-up roller 17 and is set in a position where it can be fed.

In addition, by mounting this paper feed cassette 15, the paper size detection sensor 44 blocks the optical path of only the photo interrupter sandwiching the light shielding part of the size identification light shielding plate, so that a corresponding signal, that is, a code indicating the paper size, is blocked. can be output to the control unit.

Furthermore, when the paper feed cassette 15 is not installed, the fiber 48 is in a position where it enters the paper end detection sensor 49 and blocks its optical path, as shown by the imaginary line, and the bottom plate 42 is pushed up and the topmost When the tip is pushed up by the paper, it rotates in the clockwise direction, whereby the light shielding plate 47 comes out of the paper end detection sensor 49 and unblocks the optical path.

As a result, the output signal of the paper end detection sensor 49 changes, and by detecting this change, the control section can determine whether or not there is paper in the paper feed cassette 15.

Note that a notch (not shown) is formed in the portion of the bottom plate 42 that faces the fish 48, and when the bottom plate 42 is raised with no paper placed on it, the fish 48 is rotated upward by the cutout. Therefore, the control unit detects that there is no paper.

Here, the paper feed cassette 15 and its surrounding parts have been explained, but the other paper feed cassettes 16°40.41 and their surrounding parts have the same configuration as in FIG. 5, so their illustration and explanation will be the same. is omitted.

FIG. 6 is a block diagram showing the control section of this copying machine.

This entire control unit is a microcomputer (rCPU)
The CPU 50 includes a ROM 51 that stores control programs and fixed data, and various data (various codes, counter values, etc.).

A decoder 53 for serial communication, a clock IC 54 that outputs data indicating the current time, and an analog interface that connects various analog sensors such as the P sensor 39 shown in FIG. 4. 5
5, a digital interface 56 that connects various digital sensors such as the paper size detection sensor 44, paper end detection sensor 49, and interlock sensor shown in FIG. 5, and 2 that connects various cross current loads such as motors and clutches. AC load interfaces 57 and 58, and a control CPU for the automatic document feeder (hereinafter abbreviated as rADFJ).
An optical communication interface 59 is connected thereto.

Note that the control CPU of the ADF is a microprocessor that controls the feeding and discharging of documents while communicating with the CPU 50. The communication information includes document presence/absence information on the document table and copy start information given from the ADF control CPU to the CPU 50, document set/update information given from the CPU 50 to the ADF control CPU, and the like.

The power source of this copying machine is a commercial power source, and the power supply unit 60
Constant voltage Vcc for logic loads such as the CPU 50 and various sensors (including timer display) generated from commercial power supply in
, constant voltage VL for light loads such as displays (excluding timer displays), etc.
t and a constant voltage vH for heavy loads such as motors and clutches are supplied to each part.

Further, a backup power source 61 is also connected to the RAM 52 and the clock IC 54 in order to prevent internal data from disappearing when the commercial power source is cut off.

The serial communication decoder 53 is connected to an operation panel, an optical system (various drivers), a slave CPU, an eraser clock, a relay driver 62, etc., which will be described later, and sends and receives data to and from the CPU 50 by serial communication.

The relay driver 62 receives the CP obtained through the decoder 53.
In response to the instruction from U50, a solid steady relay (SSR) 63 inserted into the light load constant voltage VL supply line of the power supply unit 60 and a heavy load constant voltage vH supply line are connected. The solid steady relays 64 are turned on and off independently.

FIG. 7 is a layout diagram showing an example of the configuration of the operation panel 70.

This operation panel 70 includes a copy start key 71, If
Number confirmation (#) key 72. Numeric keypad 73. Guidance key 74. Paper selection key 75. And keys such as cover key 78 etc.
A group of key switches, a guidance display 76, and paper information displays 77a to 77d.

and a group of indicators such as cover mode indicators 79 and 80.

The copy start key 71 is a key for starting a copy operation.

The set number confirmation key 72 is used to confirm the number of sheets set during copying, to change dimensions or set a program, and to set a specific paper feed cassette according to the present invention.

The numeric keypad 73 is used to set the number of copies, change the dimensions, set the binding margin width, set a program, and when you want to set a specific paper feed cassette.

The guidance key 74 is used when it is desired to display a copy operation method and an explanation of each key operation on the guidance display 76.

Paper selection key 75 is used when selecting copy paper.

The cover key 78 is a key used when setting cover mode 1 or 2.

Here, cover mode 1 is a mode in which the first document is copied onto a specific paper (cover for bookbinding) as a specific document when performing continuous copying using the ADF, and cover mode 2 is a mode in which the first document is copied onto a specific paper (cover for bookbinding). This is a mode in which the first original and the final original are copied onto a specific paper as a specific original.

The guidance display 76 can display explanations of various functions, operating procedures, and conditions inside the aircraft.

The paper information displays 77a to 77d respectively correspond to the four paper feed cassettes 15, 16, 40, and 41 shown in FIG.
The paper size, etc. can be displayed on the display corresponding to the paper feed cassette.

The cover mode indicator 79 lights up when cover mode 1 is selected by operating the cover key 78, and the cover mode indicator 80 lights up when cover mode 2 is selected.

Note that the other key switches and indicators are not directly related to the present invention, so their explanations will be omitted.

Next, the operation of this embodiment configured as described above will be specifically explained with reference to FIG. 8 and subsequent figures.

FIG. 8 is a flowchart showing specific paper feed cassette setting processing by the CPU 50 of FIG.

This routine starts when called by the main routine (not shown). First, it is determined whether or not the paper feed input force mode is selected. If it is not the paper feed input force mode, press "1" on the numeric keypad 73 shown in FIG. The process moves on to determining whether or not a key has been pressed.

If the "1" key of the numeric keypad 73 is not pressed, the process immediately returns to the main routine, and if it is pressed, it is determined whether or not the number confirmation (#) key 72 has been pressed, and if it is not pressed, the 9 key remains as is. , when pressed, returns to the main routine after entering the paper feed setting input mode.

In other words, press the "1" key on the numeric keypad 73 and confirm the number (#)
When the key 72 is pressed at the same time, the paper feed setting input mode is entered.

On the other hand, in the paper feed setting input mode, press "1" on the numeric keypad 73.
Determine whether or not any of the "4" keys has been pressed, and if pressed, store the input key number as a specific paper feed cassette, cancel the paper feed setting input mode, and return to the main routine. do.

Here, the identification codes (IDs) of the four paper feed cassettes 15, 16, and 40° 41 are each "1".

If the numbers are "2", "3", and "4", for example, if the "1" key of the numeric keypad 73 is pressed during the paper feed setting input mode, that key number "1" will be stored as a specific paper feed cassette. Therefore, the paper feed cassette 15 indicated by the key number is set as a specific paper feed cassette.

Further, when the rQJ key of the numeric keypad 73 is pressed in the paper feed installation mode, it is stored that the specific paper feed cassette does not exist, and then the process returns to the main routine.

Therefore, when the "0" key of the numeric keypad 73 is pressed in the paper feed setting input mode while any paper feed cassette is set as a specific paper feed cassette, the setting state is canceled.

FIG. 9 is a flowchart showing cover mode setting processing by the CPU 50.

This routine also starts when called by the main routine, and first checks whether or not the cover key 78 shown in FIG. 7 has been pressed. If not, the cover key set flag (FG) is reset to 1101+. and return to the main routine. It should be noted that the cover key set flag is a flag for detecting the activation of the key force by the cover key 78.

Furthermore, when the cover key 78 is pressed, it is determined whether the cover key set flag is 44171, and the it l
If it is rt, return to the main routine, and if it is not pa 1'', set it to #I I+, then cover mode l
is set.

If cover mode 1 is set, cover mode 1 is canceled and cover mode 2 is set, and the process returns to the main routine. If cover mode 1 is not set, cover mode 2 is set. If cover mode 2 is set, it is canceled, and if cover mode 2 is not set, cover mode 1 is set and the process returns to the main routine.

Therefore, it can be seen that every time the cover key 78 is pressed, cover mode 1→cover mode 2→cover mode cancellation is repeated.

FIG. 10 is a flowchart showing paper feed switching check processing by the CPU 50.

When called and started by the main routine,
First, in step 1, it is determined whether or not copying is in progress. If copying is not in progress, the process returns to the main routine. If copying is in progress, it is determined in step 2 whether or not the paper in the selected paper cassette is at the end of paper. .

If the paper is not at the paper end, the process returns to the main routine, and if the paper is at the paper end, the process proceeds to step 3 where it is determined whether or not this paper cassette is a specific paper cassette, that is, whether it is set as a specific paper cassette. If the judgment is made and the paper feed force is a certain one, the process immediately proceeds to step 16.
The copying is then interrupted and the process returns to the main routine.

If the paper cassette is not a specific paper cassette, the paper size to be stored in the first paper cassette 15 in step 4 is the same as the paper stored in the selected paper cassette. If they are the same size, the process proceeds to step 7, but if they are the same size, the process proceeds to step 5, where it is determined whether the first paper feed cassette 15 is a specific paper feed cassette.

If the paper feed cassette 15 has a specific paper feed power set, the process proceeds to step 7, but if not, it is determined in step 6 whether or not the paper feed cassette 15 is at the paper end. At step 17, the paper feed is switched to feed paper from the paper feed cassette 15, and then the process returns to the main routine.

If the paper in the paper feed cassette 15 is full, the process advances to step 7, and the paper size to be stored in the second paper feed cassette 16 is stored in the selected paper feed cassette. It is determined whether or not the size is the same as that of the paper cassette 16, and the same process as that for the paper cassette 15 described above (excluding the copy interruption process in step 16) is performed on this paper cassette 16 in steps 8, 9, and 17. In Steps 10 to 15, the same processing as described above is performed for the paper feed cassettes 40.-41 in the rowless 1, third and fourth stages.

If the process advances to step 16, the copying is interrupted and the process returns to the main routine.

FIG. 11 is a flowchart showing paper feeding start processing by the CPU 50.

This routine is called and started by the main routine when an automatic document feeding mode, that is, a mode in which continuous copying is performed using an ADF, is set and a document is fed from the document table.

First, check whether the document fed from the document table of the ADF is the first sheet, and if it is the first sheet, cover mode 1 is selected.
or 2 is set, and if neither cover mode is set, paper feeding is started from the currently selected paper feeding cassette and then the process returns to the main routine.

Also, if cover mode l or 2 is set, it is determined whether a specific paper feed cassette is selected, and
If it is selected, paper feeding starts from that paper cassette, and if it is not selected, it is determined whether or not there is a specific paper cassette, that is, each paper cassette 15 shown in FIG.
Check whether any one of 16, 40, 41 is set as a specific paper feed cassette.

Then, if there is no specific paper feed cassette, the process returns to the main routine, and if there is, it is determined whether or not there is paper in it. After that, return to the main routine.

On the other hand, if the fed document is not the first one, it is determined whether or not it is the final document, and if it is not the last document, paper feeding is started from the currently selected paper cassette, and then the main Return to routine.

Also, if the fed document is the final document.

It checks whether cover mode 2 is set or not, and if it is set, it moves on to checking whether a specific paper feed cassette is selected and performs the same process as described above, and if cover mode 2 is set. If not set, paper feeding is started from the currently selected paper feeding cassette, and then the main routine returns.

Note that the final document is determined based on a signal from the ADF.

In other words, when a document is fed and there is no document left on the document table, the control CPU on the ADF side detects this using a signal from the document detection sensor, and treats the fed document as the final document and sends it to the copying machine. The CPU 50 is notified of this.

Thereby, the CPU 50 can determine the final manuscript.

In this embodiment, during copying, when paper is being fed from a paper cassette that is not set as a specific paper cassette among the four paper cassettes 15, 16, 40. If it is detected that there is no paper for that paper cassette, try using another paper cassette that stores paper of the same size as the paper that was stored in that paper cassette and that is not set as a specific paper cassette. If there is a paper cassette, it will automatically switch to feeding paper from that paper cassette, so if special paper is set in a specific paper cassette and has a different quality or color than normal paper, Even if normal paper is fed from another paper feed cassette and image formation is performed and the paper runs out, unnecessary image formation will not be performed by switching to an undesired paper.

Also, when paper is being fed from a specific paper cassette, if no paper is detected for that paper cassette, paper of the same size as that stored in that paper cassette will be loaded. Even if there are other paper cassettes stored in the paper cassette, switching the paper source is prohibited so that paper is not fed from that cassette, so it is possible to set special paper in a specific paper cassette and form an image. Even if the paper runs out during the process, unnecessary image formation will not be performed by switching to another undesired paper.

Furthermore, when automatic document feeding mode and cover mode 1 or 2 are set, when forming an image using a document, if the document fed from the document table is the first or final document. , and if there is paper in a specific paper feed cassette, it will be fed, which is very convenient when binding a book.

Note that the present invention is applicable not only to copying machines but also to various image forming apparatuses such as various printers including laser printers and facsimile machines.

〔Effect of the invention〕

As explained above, according to the image forming apparatus according to the present invention, when a special paper of different paper quality, color, etc. from normal paper is set in one of the paper feed stages, Even if the paper runs out when forming an image by feeding paper from a paper feed tray containing other normal paper, the image is formed using another undesired paper, resulting in wasted image formation. disappears.

In addition, when forming an image using a document, when a specific document is identified among multiple documents to be used, a predetermined paper feed tray can be set as the specific paper feed tray, and a specific document image can be created using a predetermined paper feed tray. I decided to copy it to a specific paper, so
This is very convenient when binding books.

[Brief explanation of the drawing]

Figures 1 to 3 are functional block diagrams showing the basic configuration of each invention, respectively. Figure 4 is a schematic configuration diagram showing an example of a copying machine equipped with a plurality of paper feed stages in which the invention is implemented. Figure 5 is a Similarly, FIG. 6 is a block diagram showing a control section of the copying machine shown in FIG. 4, and FIG. 7 is a diagram showing an example of the configuration of the operation panel 7o. 8 is a flowchart showing the specific paper feed stage setting process by the CPU 50 in FIG. 6, FIG. 9 is a flowchart showing the cover mode setting process by the same CPU 50, and FIG. 5 is a flowchart showing paper switching check processing. FIG. 11 is a flowchart showing paper feeding start processing by the same CPU 50. 15. 16, 40, 41...Paper feed cassette 44...
Paper size detection sensor 49...paper end detection sensor 50...microcomputer ('cpu) 51...
・ROM 52...RAM71...Copy start key 72...Number confirmation (#) key 78...Cover key 79.80...Cover mode display 73...Numeric keypad 1 Figure 2 Figure 3 Figure 9 Figure 11

Claims (1)

[Claims] 1. A plurality of paper feed stages, a paper presence/absence detection means for detecting the presence or absence of paper in each paper feed stage, and a paper size for detecting the size of paper stored in each paper feed stage. a detecting means; during image formation, when paper is being fed from a paper feed stage selected from the plurality of paper feed stages, if it is detected that there is no paper in the paper feed stage; An image provided with an automatic paper feed switching means that automatically switches to feed paper from another paper feed stage that stores paper of the same size as the paper stored in the tray if there is another paper feed stage that stores paper of the same size. In the forming apparatus, a specific paper feed cassette setting means sets one of the plurality of paper feed cassettes as a specific paper feed cassette; When paper is being fed from the paper tray, if it is detected that there is no paper in the paper feed tray, paper of the same size as the paper that was stored in the paper feed tray is stored. 1. An image forming apparatus comprising: a switching prohibition means for prohibiting the paper feed automatic switching means from switching the paper feed even if there is a paper feed stage. 2. A plurality of paper feed trays, a paper presence/absence detection means for detecting the presence or absence of paper in each paper feed tray, a paper size detection means for detecting the size of paper stored in each paper feed tray, and an image forming device. In the middle, when paper is being fed from a selected paper feed cassette among the plurality of paper feed cassettes, if no paper is detected for that paper feed cassette, the paper is stored in the paper feed cassette. In an image forming apparatus, the image forming apparatus includes an automatic paper feed switching unit that automatically switches to feed paper from another paper feed stage that stores paper of the same size as the paper size, if there is another paper feed stage that stores paper of the same size as the paper size, a specific paper feed cassette setting means for setting one of the paper feed cassettes as a specific paper feed cassette; When the paper is out of paper is detected for the paper feed tray,
Only when there is a paper feed tier other than the specific paper feed tier that stores paper of the same size as the paper stored in the paper feed tier, the automatic paper feed switching means is allowed to switch the paper feed. An image forming apparatus comprising: a switching permission means. 3. The image forming apparatus according to claim 2, further comprising a specific document discriminating means for discriminating a specific document from among a plurality of documents used when forming an image using a document; The image forming apparatus is characterized in that when forming an image using a specific document, the specific paper feed cassette setting means sets a predetermined paper feed cassette as the specific paper feed cassette.