JPH10239929A - Recording-paper supply device for image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a jam of fresh recording paper by stopping an image forming operation as it is and inhibiting the switching of a paper feed part, in the case a roll of paper runs out before the completion of image formation on a specified number of sheets of paper during a consecutive image-forming process using the roll of paper. SOLUTION: When recording paper in a selected paper-feed part is used up and there is no more paper left, a paper-absence-signal is transmitted to the paper switch means 31a of a paper supply control part 30 from one of paper presence/absence sensors 20a, 14a, and 28a. Then, it judges whether the paper feed part which has been selected and involved in the copying operation is a roll unit or not, that is, whether a roll of recording paper has been used or not. In the case the paper feed part selected at present is the roll unit, the copying operation is finished as it is. Thus, by finishing the copying operation in the case there is no more roll of paper left in the roll unit, flesh recording paper is not fed even if a piece of recording paper from the roll unit stays in a carrying path, and, thus, a paper jam does not occur.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic copying machine,
The present invention relates to a recording sheet supply device of an image forming apparatus provided with a plurality of sheet feeding units for an image forming apparatus such as an electrostatic recording apparatus.

[0002]

2. Description of the Related Art In general, in various image forming apparatuses such as an electrophotographic copying machine, an original is placed in a fixed or moving state on an original glass table, and an illumination lamp or the like constituting image reading means is attached to the original. The original image is read by moving the image relative to the image, an electrostatic latent image corresponding to the image is formed on the image carrier, developed, and the obtained toner image is transferred onto recording paper to form an image. I'm trying to do it.

As recording paper used in such an image forming apparatus, other recording paper such as cut paper cut in advance to a predetermined size, roll paper in which a long recording paper is wound into a cylindrical shape, postcard, and the like are used. There are papers, and each of these recording papers is appropriately stored in each paper feed unit of a paper feed cassette, a roll unit, and a manual feed tray, and is selected from among the plurality of paper feed units in accordance with a document. The recording paper is pulled out from one paper supply unit in synchronization with the image forming process.

That is, a plurality of paper feed units including the above-mentioned paper feed cassette, roll unit, and manual feed tray selectively perform a paper feed operation based on a command issued from a paper feed control unit. The recording paper pulled out from the paper section is conveyed to a transfer area and is discharged after the transfer. The long recording paper drawn from the roll unit is used after being cut to a required size by a cutting means such as a cutter.

On the other hand, each of the above-mentioned paper feed units is provided with a paper presence / absence sensor for detecting the presence / absence of recording paper in each paper feed unit. If the recording paper runs out in the paper feed unit during the continuous paper feed operation, a "paper out signal" is output from the paper presence / absence sensor in the paper feed unit to the paper supply control unit. If the paper feed control unit is provided with a paper switching means (auto change mechanism), the "paper out signal"
In response to a command issued from the paper switching means based on the condition, the paper supply unit in the paper-out state is immediately switched to another paper supply unit holding the recording paper, and the switched other paper supply unit is switched. The paper feeding operation from the paper section is continuously performed without stopping due to the absence of paper.

[0006]

However, in the conventional apparatus, when the paper feeding unit where the paper feeding operation is being performed continuously is a roll unit, the roll paper in the roll unit has a set number of images. If the paper is removed before forming, the paper feeding operation is switched to the paper feeding cassette or the manual feed tray which is another paper feeding unit, and the switching may cause a paper jam. In other words, when the recording paper is exhausted from the roll body in the roll unit in use, the length of the last remaining recording paper piece may be so short that it cannot be transported. In the middle, the recording paper piece does not reach the roller located on the downstream side in the transport direction, and the recording paper piece stays in the transport path. When new recording paper is fed from another paper feeding unit such as a paper feed cassette in such a paper jam state, the progress of the new recording paper is obstructed by the staying recording paper pieces, and the paper jam occurs. It will cause.

Accordingly, the present invention has been made to solve the above problem and to prevent the occurrence of paper jam when the recording paper runs out during the image forming process using the recording paper in the roll unit. It is an object of the present invention to provide a recording paper supply device for an image forming apparatus.

[0008]

According to a first aspect of the present invention, there is provided a recording paper supply device for an image forming apparatus, comprising: a roll body formed by winding a long recording paper into a cylindrical shape. A plurality of paper feed units including a roll unit to be housed as one paper feed unit; a paper presence / absence sensor for detecting the presence / absence of recording paper in each of the paper feed units; and one of the plurality of paper feed units A paper supply control unit for pulling out recording paper from one selected paper supply unit in synchronization with an image forming process and performing a paper supply operation to a transfer area at a predetermined timing; In the paper supply device, the paper supply control unit receives a paper absence detection signal output from the paper presence / absence sensor when the recording paper of the paper supply unit that is currently supplied runs out before the end of image formation, Keep the recording paper
Switch to another paper feed portion which is perforated, and has a paper switching means for causing the sheet feeding operation from the switched paper feed unit, the paper switching means includes a sheet feeding portion is roll unit became no paper state In the case of, a function to stop the image forming operation is provided.

According to such an apparatus, when the recording paper runs out during the image forming process using the recording paper in the roll unit, the image forming operation is stopped as it is, and the paper feeding unit is switched. No paper is fed from another paper feed unit, and paper jams occur even if the last piece of recording paper pulled out of the roll unit roll stays in the transport path. I will not do it.

According to a second aspect of the present invention, there is provided a recording sheet supply device for an image forming apparatus, wherein the sheet switching means in the sheet supply control unit according to the first aspect is configured such that the sheet supply unit in a paper-out state is a roll unit. In the case of a paper supply unit other than the above, a function is provided for switching to another paper supply unit holding recording paper to perform a paper supply operation.

According to such an apparatus, when the image forming process is performed using the recording paper in a paper supply unit other than the roll unit such as the paper supply cassette, the paper supply cassette or the like is in a paper-free state. The recording paper last pulled out just before the recording paper has a predetermined size, so that the paper cannot be transported due to the small size, and the other paper feeding unit continues. Even if a paper feeding operation is performed from the beginning, a paper jam state does not occur because the progress of a new recording sheet is not hindered, and the image forming operation can be continued without interruption. I have.

According to a third aspect of the present invention, there is provided a recording paper supply apparatus for an image forming apparatus, wherein a paper supply unit other than the roll unit according to the second aspect includes a paper supply unit for accommodating recording paper previously cut to a predetermined size. A paper cassette and a manual tray for storing arbitrary recording paper, and a paper switching unit of the paper supply control unit is configured to supply another paper holding recording paper from the paper cassette or the manual tray in a paper-out state. It has a function of setting a priority order for a cassette or a manual feed tray and performing switching selection.

According to such an apparatus, when the image forming process is continuously performed using the recording paper in the paper feed unit of the paper feed cassette or the manual feed tray, there is no paper before the set number of images is formed. In the state, the other sheet feeding cassette , the manual feed tray or the roll unit is switched with a predetermined priority, so that the switching operation is performed without causing unnecessary confusion.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Prior to this, an outline of an image forming apparatus will be described using an electrophotographic copying machine as an example.

In the electrophotographic copying machine shown in FIG. 1, a document glass table 2 as a document table is provided on an upper surface of an apparatus main body 1 and a document glass table 2 is provided immediately below the document glass table 2. And a scanner (scanning optical device) 3 constituting an image reading means. The scanner 3 has an illumination lamp 3a for irradiating scanning light to a document (not shown) on the document glass table 2, and guides reflected light from the document onto a photosensitive drum 4 described later. It includes a reflection mirror 3b and a projection lens 3c.

An original supply device 5 is provided on the original glass table 2 so as to cover the original glass table 2 so as to be openable and closable. The original supply device 5 includes the illumination lamp 3
a is stopped at a predetermined position, and a document feeder (DF) 5a for scanning (sheet through) for reading while transporting the document onto the document glass table 2; An automatic document feeder (AF) 5b that stops at a position and reads while moving the illumination lamp 3a
It is composed of

A photosensitive drum 4 as an image carrier is provided below the scanner 3 so as to be driven to rotate clockwise in the drawing. This photosensitive drum 4
A charger 6 uniformly charges the photosensitive drum 4 and supplies toner to an electrostatic latent image formed on the photosensitive drum 4 by exposing the scanning light from the scanner 3 to light. A developing device 7 for developing an image, a transfer charger 8 disposed in the middle of the paper transport path to transfer the toner image on the photosensitive drum 4 to the recording paper side, and a separation device for separating the recording paper after the transfer A charger 9, a cleaning device 10 for removing toner remaining on the photosensitive drum 4 after transfer, and the like are sequentially arranged along a rotation driving direction of the photosensitive drum 4.

Further, the toner image on the recording paper is thermally fixed to the exit side end of the belt-shaped paper transport path 11 extending from the transfer charger 8 and the separation charger 9 toward the exit of the apparatus main body. And a discharge tray 13 is mounted at an outlet of the fixing device 12. Further, a paper feed cassette 14 for storing cut recording paper for each size is provided directly below the belt-shaped paper transport path 11 so as to form a four-stage paper feed unit.

At the outlet on the right side in the drawing of each of the paper feed cassettes 14, paper feed rollers 15 are arranged, respectively, and a transfer area of the photosensitive drum 4 from the paper feed rollers 15 of each of the paper feed cassettes 14 is provided. Transport path 16 toward
Extend respectively. Each of these transport paths 16 merges into a single transport path 17, and a registration roller 18 that feeds the recording paper to the transfer area in the vicinity of the transfer area in the merged transport path 17 in synchronization with the image forming process.
Is provided.

In the vicinity of each of the paper feed rollers 15,
A cassette paper presence / absence sensor 14a for detecting the presence / absence of recording paper in each paper cassette 14 is provided, and when there is no recording paper in each paper cassette 14, the presence / absence of a cassette paper corresponding thereto is detected. Sensor 14
The "a out of paper signal" is issued from "a".
The “paper out signal” from the cassette paper presence sensor 14a
Is received by the paper supply control unit 30 as described later.

Further, a roll unit RU integrally provided with a roll body 20 and the like is provided on a side portion (right portion in the drawing) of each of the paper feed cassettes 14 so as to face rightward in the drawing with respect to the main body of the copying machine. It is provided so that it can be pulled out. As shown in FIG. 2, the roll body 20 is formed by winding a long recording paper into a cylindrical shape, and includes a roll unit R.
U, which is exchangeably mounted inside the U.
When the recording paper of zero is consumed and runs out, it is configured to be replaced with a new roll.

As shown in FIG. 2, a transport path 21 for transporting the recording paper drawn from the roll body 20 is provided above the roll body 20. The path 21 corresponds to the registration roller 1 described above.
It is connected so as to be connected to the merging and conveying path 17 toward 8. In the middle of the transport path 21, a paper feed roller 22 and a transport roller 23 constituting a roll paper transport mechanism are arranged on the upstream side and the downstream side in the transport direction, respectively.
The recording paper is pulled out from the roll body 20 in synchronization with the copying operation by the rotational driving force of each of the rollers 22 and 23, and the recording paper is conveyed toward the transfer area.

Further, a cutter 24 is provided between the paper feed roller 22 and the transport roller 23 as cutting means for cutting the recording paper drawn from the roll body 20 into a predetermined length. The cutter 24 has a rotary blade that moves so as to cross in the paper width direction, and the rotary blade is configured to be operated at a predetermined timing. The recording paper that has passed through the cutter 24 draws a loop R having a sufficient length in consideration of the cutting time so that the recording paper can be cut even during image formation. Thus, the rear end of the recording paper can be stopped even when the transport roller 23 is in the middle of transport.

Further, a roll paper presence / absence sensor 20 for detecting the presence / absence of recording paper in the roll body 20 is provided upstream (lower side in the drawing) of the paper feed roller 22 in the transport direction.
a is arranged. This roll paper presence sensor 20a
When the recording paper in the roll body 20 runs out,
It has a function of issuing a "paper-out signal" by detecting the trailing end of the recording paper that has been pulled out last. The “paper absence signal” from the roll paper presence / absence sensor 20a is also received by the paper supply control unit 30 described later.

On the other hand, on the downstream side (the left side in the drawing) of the paper feed roller 22 in the conveying direction and the upstream side (the right side in the drawing) of the cutter 24, the leading end position of the recording paper is read, and the conveyance amount of the recording paper is measured. Feed sensor 2 that generates a trigger signal
7 are arranged. That is, the transport amount of the recording paper pulled out from the roll body 20 is configured to be read based on the transport amount by the paper feed roller 22 after the paper feed sensor 27 detects the leading end of the recording paper. I have. Further, a registration sensor 26 for detecting a paper conveyance state with respect to the registration roller 18 is arranged on the upstream side (right side in the drawing) of the registration roller 18 in the conveyance direction.

Returning to FIG. 1, a manual feed tray 28 is attached to the upper part of the roll unit RU so as to project obliquely upward from the side of the copying machine body.
A manual feed path 28a extending from the manual feed tray 28 into the copying machine main body is provided so as to be inclined obliquely downward. At the lower end exit of the manual feed tray 28, a manual feed roller 29 for feeding recording paper of an arbitrary size placed on the manual feed tray 28 toward the manual feed path 28a is provided. The manual feed path 28a
Is connected so as to be connected to the above-described convey path 17 to the registration roller 18.

In the vicinity of the manual paper feed roller 29, a manual paper presence / absence sensor 28b for detecting the presence / absence of recording paper on the manual paper feed tray 28 is arranged.
The manual paper presence sensor 28b normally generates a "paper no signal" by being kept in the off state, but detects the front end of the recording paper when the recording paper is placed on the manual feed tray 28. By doing so, a function of issuing a "paper present signal" is provided. The “paper absence signal” and the “paper presence signal” from the manual paper presence / absence sensor 28b are also received by the paper supply control unit 30 described later.

On the other hand, the paper supply control unit 30 shown in FIG.
Are the roll unit RU, the paper cassette 14,
A sheet feeding operation in which a recording sheet is pulled out from a sheet feeding unit appropriately selected corresponding to a document from a sheet feeding unit of the manual feed tray 28 at a predetermined timing together with the start of a copying operation and fed to a transfer area. If the recording paper pulled out from the selected paper feed unit runs out before the end of the set number of copies during the continuous copy operation,
It has a function of performing a paper-out control operation as described later.

The paper supply control unit 30 has a structure as shown in FIG. 3, and is provided with a paper switching means 31 provided in a central processing unit (hereinafter referred to as a CPU) 31.
The input unit of a includes a roll paper presence / absence sensor 20a disposed on the roll unit RU, a cassette paper presence / absence sensor 14a disposed on each paper feed cassette 14, and a manual paper presence / absence sensor 28a disposed on the manual feed tray 28. The “paper presence / absence detection signal” is applied, and a control program or the like that defines a recording paper conveyance procedure described later is stored in the RO.
A “read signal” from M32 and a “read / read signal” from RAM 33 storing various data are input.

The output of the paper switching means 31a of the CPU 31 includes the paper feed rollers 22, 15, and 29 disposed in the paper feed units of the roll unit RU, the paper feed cassette 14, and the manual feed tray 28, respectively. Motor driver 3 for each of motors 22a, 15a, 29a for driving
4, 35, 36 are connected to each other, and drive signals are output to these drive drivers 34, 35, 36 at a predetermined timing. That is, the paper switching means 31a is provided with each of the paper feed units RU,
Paper presence / absence sensors 20a, 14a, 14a, 14a, and 14a corresponding to the paper supply unit selected in the current copy operation.
When a "paper out signal" is received from any one of the paper supply units 28a, it is recognized that the currently selected paper supply unit is in a paper out state, and the paper supply unit is switched to another paper supply unit holding the recording paper and selected. Has a function.

The control operation of the paper switching means 31a will be specifically described with reference to the flowchart shown in FIG. At the start of the copy operation, first, the roll unit RU,
Either the paper feed unit of the paper feed cassette 14 or the manual feed tray 28 is automatically or manually selected, and as shown in FIG. 4, the recording paper from the selected paper feed unit is started by the start of the continuous copy operation. When the recording paper is sequentially pulled out and there is a recording paper in the selected paper feeding unit (Yes in step 1)
s) As long as the selected paper feed unit holds the recording paper, the copy operation is continued up to the set number of sheets.

On the other hand, when the recording paper in the selected paper feed unit is consumed and exhausted, the paper presence / absence sensors 20a, 14a, 28a
A "paper out signal" is issued to the paper switching means 31a of the paper supply control unit 30 from either of the above. Then, first, the paper feeding unit that has been selected and performing the copying operation is the roll unit R.
U, that is, whether or not the recording paper of the roll body 20 is used (step 2). If the currently selected paper feed unit is the roll unit RU (step 2). Yes), the copy operation is terminated as it is (step 3).

The copying operation is terminated as described above for the following reason. In other words, when the paper feeding unit that has been performing the paper feeding operation is the roll unit RU, the length of the last sheet of the recording paper may be short enough to be unable to be conveyed. The last piece of paper may be jammed halfway. In spite of such a paper jam, a paper jam occurs when the paper feeding operation is performed by switching to another paper feeding unit. On the other hand, as described above, if the copy operation is terminated when the roll paper of the roll unit RU runs out, even if a recording paper piece from the roll body is staying in the transport path, new recording is performed. Since paper is not fed, paper jam does not occur.

Also, the paper feed unit selected and performing the copy operation is not the roll unit RU but the paper feed cassette 1
4. In the case where any of the paper feed units of the manual feed tray 28 is used (No in step 2), when the selected paper feed unit runs out of recording paper, first the paper feeder holding the recording paper It is determined whether or not there is another copy (step 4), and if there is no other paper supply unit holding the recording paper (No in step 4), the copy operation is terminated as it is (step 5).

On the other hand, when there is no recording paper in the paper supply cassette 14 and the manual feed tray 28 as the selected paper supply unit, if there is another paper supply unit holding the recording paper (step 4). Yes), it is checked whether or not the recording paper is the same size as the recording paper in the original paper feed unit (step 6). If there is a recording paper of the same size (Yes in step 6), The copy operation is continued by immediately switching to the paper feed unit (step 7). This is because, even if the copy operation is continued, no jam of the recording paper occurs, so that the copy operation can be satisfactorily continued without interruption. If there is no recording paper of the same size (No in step 6), the copying operation is terminated (step 5).

As described above, when switching the paper feed unit to another one, a predetermined priority is set for the paper feed unit. For example, in the above-described embodiment, the paper feed cassette 14, the roll unit RU, The paper feed units are selected in the priority order of the manual feed tray 28. By setting such priorities, unnecessary confusion of the sheet feeding operation is prevented.

Although the invention made by the inventor has been specifically described based on the embodiment, the invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the invention. Needless to say. For example, the present invention includes a copier, a facsimile,
The present invention can be similarly applied to various image forming apparatuses such as a printer.

[0038]

As described above, the recording paper supply device of the image forming apparatus according to the first aspect of the present invention provides a method for recording a set number of images in a continuous image forming process using roll paper before terminating the formation of a predetermined number of images. When the roll paper is exhausted, a paper switching unit is provided to stop the image forming operation and not switch the paper feeding unit, so that even if a roll paper piece stays in the conveyance path, new recording is performed. Since the paper is not fed, the occurrence of paper jam of new recording paper can be favorably prevented, and the reliability of the image forming apparatus can be improved.

According to a second aspect of the present invention, there is provided a recording sheet supply device for an image forming apparatus, wherein a recording sheet supply device other than a roll unit such as a sheet cassette in addition to the recording sheet supply device according to the first aspect. 2. The effect of the invention according to claim 1, further comprising a paper switching unit for continuously performing a paper feeding operation from another paper feeding unit when the image forming process is continuously performed using the recording paper. In addition, when recording paper other than roll paper is used, the image forming operation can be favorably continued without interruption, and the reliability of the image forming apparatus can be further improved.

According to a third aspect of the present invention, there is provided a recording sheet supply device for an image forming apparatus, wherein a priority order is set for a sheet supply unit in addition to the recording sheet supply device according to the second aspect. 2. The printer according to claim 1, further comprising a paper switching means for switching.
In addition to the effects of the present invention, it is possible to prevent unnecessary confusion of the sheet feeding operation when the switching operation of the sheet feeding unit is performed, and it is possible to further improve the reliability of the image forming apparatus.

[Brief description of the drawings]

FIG. 1 is a cross-sectional explanatory view showing a copying machine as an example of an image forming apparatus to which the present invention is applied.

FIG. 2 is an explanatory cross-sectional view showing an enlarged structure example of a roll unit used in the copying machine shown in FIG. 1;

FIG. 3 is a block diagram illustrating a paper supply control unit according to an embodiment of the present invention.

FIG. 4 is a flowchart showing a sheet feeding unit selection processing operation performed by a sheet switching unit of the sheet supply control unit shown in FIG. 3;

[Explanation of symbols]

 Reference Signs List 14 paper feed cassette 14a cassette paper presence sensor RU roll unit 20 roll body 20a roll paper presence sensor 22 paper feed roller (roll paper transport mechanism) 23 transport roller (roll paper transport mechanism) 24 cutter (cutting means) 27 paper feed sensor 28 Manual tray 28a Paper presence / absence sensor 29 Paper feed roller 30 Paper supply control unit 31 Central processing unit (CPU) 31a Paper switching means

Claims (3)

[Claims] A plurality of paper feed units each including a roll unit accommodating a roll body formed by winding a long recording paper into a cylindrical shape; A paper presence / absence sensor for detecting the presence / absence, and pulling out recording paper from one of the plurality of paper supply units in synchronization with the image forming process, and transferring the recording paper to the transfer area at a predetermined timing. And a paper supply control unit for performing a paper supply operation of the recording paper supply unit of the image forming apparatus, wherein the paper supply control unit is configured to determine whether the recording paper of the paper supply unit that is currently supplied is before the image formation is completed When a paper-out detection signal is output from the paper presence / absence sensor when the paper has run out, the paper is switched to another paper-supply unit holding the recording paper, and the paper supply operation is performed from the switched paper-supply unit. Switching means, wherein the paper switching means is paper Recording sheet feeding device of the image forming apparatus sheet feeding portion in a state to is characterized in that it comprises a function of stopping the image forming operation when a roll unit. 2. A paper switching unit in a paper supply control unit according to claim 1, wherein the paper supply unit in a paper-out state holds a recording paper when the paper supply unit other than the roll unit is a paper supply unit. A recording paper supply device for an image forming apparatus, comprising a function of performing a paper supply operation by switching to another paper supply unit. 3. The paper supply unit other than the roll unit according to claim 2, wherein the paper supply unit is a paper supply cassette for storing recording paper pre-cut to a predetermined size and a manual feed tray for storing arbitrary recording paper. The paper switching means of the unit sets and switches a predetermined priority from a paper cassette or a manual tray having no paper to another paper cassette or a manual tray or a roll unit holding recording paper. A recording paper supply device for an image forming apparatus, having a function of making a selection.