JPH07209937A - Image forming device - Google Patents

Abstract

PURPOSE:To make it possible to use recording paper whose length is more than the allowable length of maximum size by preparing a long manual insertion mode capable of using recording paper whose length is longer than convential maximum size. CONSTITUTION:In the case of using a multi-feeder machine, the long manual insertion mode capable of utilizing copying paper whose length is longer than the allowable length of maximum size to be specified is set up. Thereby a long manual insertion mode key 28 is mounted on an operation part 27. When the key 28 is depressed, a displayed mode is turned to a display indicating the long manual insertion mode, a jam detecting sensor arranged in the front of a resist roller is not driven as a residence jam detecting sensor but is driven as a sensor for measuring the length of copying paper fed by manual insertion, a measured detection value is fed back to a control part and check timing for a jam detecting sensor or the like arranged after the sensor is set up based upon the detection value. Thereby recording paper longer than the allowable length of the maximum size can be used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus,
In particular, the present invention relates to an image forming apparatus having a multi-feeder mechanism capable of forming an image using recording papers of various sizes and provided with an improved multi-feeder mechanism that can be used even for long recording papers.

[0002]

2. Description of the Related Art Generally, an electrophotographic copying apparatus, which is a kind of image forming apparatus, uses a photoconductor as an image forming medium. Then, for forming an image, a light source lamp irradiates a document on the document table to obtain reflected light from the document image,
This optical image is projected onto the exposed portion of the photoconductor by a mirror or lens to form an electrostatic latent image on the photoconductor. This electrostatic latent image is visualized on the photoconductor and transferred to the recording paper (copy paper) conveyed from the paper feed unit, and the copy paper after transfer is separated from the photoconductor and further conveyed, The transfer unit fixes the transferred image to form an image on the copy sheet, and the sheet is discharged from the sheet discharge unit to the sheet discharge tray.

Now, a paper feeding / conveying mechanism of such a copying apparatus will be described with reference to FIG. FIG. 6 is a schematic front view of the sheet feeding / conveying unit of the copying apparatus. Paper feeding cassettes 1A and 1B for feeding copy sheets are arranged in the lower portion of the apparatus main body, and the respective cassettes are provided. 1A and 1
In B, for example, A4 or B4 sheets are stored. Further, in addition to these cassettes, the multi-feeder mechanism 2 is provided, and copy paper of a desired size can be used according to the needs of the user. This multi-feeder mechanism 2 has 1
In addition to manual paper feeding one by one, it is also possible to install multiple sheets of copy paper of a specified size for continuous copying.

In such a copying machine, various copy paper detection sensors are provided to detect whether or not the copy paper is fed and conveyed normally. Sa, Sb, and Sc are sheet feeding cassettes 1A, 1
B, and a sensor for detecting whether or not copy paper exists in the multi-feeder mechanism 2. When a copy sheet is fed by either the sheet feed rollers 1a, 1b of the sheet feed cassettes 1A, 1B or the sheet feed roller 2a of the multi-feeder mechanism 2, an optical system including the above-mentioned light source lamp, mirror, lens, etc. In order to synchronize the movement of the system and the photoconductor with the copy sheet, the registration rollers 3a and 3b are temporarily stopped. When the copy sheet is conveyed in synchronism with the movement of the optical system and the copy sheet, the toner image is transferred to the copy sheet by the transfer section, separated as described above, and further conveyed by the conveying section 4. The toner image is fixed on the copy sheet transported by the transport section 4 by the fixing section 5, and an image is formed on the copy sheet. The copy sheet on which the image is formed is discharged to the discharge tray 7 by the discharge rollers 6a and 6b. A jam detection sensor is installed at a place where a jam is likely to occur in order to detect whether or not the copy paper is normally conveyed.
A jam detection sensor 8 is provided in front of the registration rollers 3a and 3b, a jam detection sensor 9 is provided after separation from the photoconductor, and a jam detection sensor 10 is provided after the discharge rollers 6a and 6b. There is.

Whether or not the copy sheet is normally conveyed is checked at a check timing of each sensor previously stored in the control unit having a microcomputer provided in the apparatus main body at the position of the sensor. It is judged whether or not it exists. This check timing differs depending on the copy paper used, and is issued to detect whether or not there is copy paper at the position of the sensor when a predetermined time has elapsed since the sensor detected the leading edge of the copy paper. To be Then, when the trailing edge of the copy sheet does not pass the position of the sensor within a predetermined time, a jam is detected.

As for the feeding / conveying of the copy sheet in the case of copying by the multi-feeder mechanism 2, the check timing of each sensor is determined in accordance with the designated size as in the case of feeding the copy sheet from the sheet feeding cassette. In consideration of a device failure due to a jam and a jam handling property, it is possible to pass a sheet having a copy sheet length up to a designated size + about 20 to 30 mm so as to issue a check timing. In this case, the longest copy paper that can be passed is the maximum size that can be specified (for example, A2 size) +20 to 30
Copy sheets up to about mm are common, and a copy sheet longer than that is detected as a jam jam because the trailing edge of the sheet does not finish passing the jam detection sensor 8 within a predetermined time.

A specific example of check timing will be described with reference to FIGS. 7 and 8. Fig. 7 shows copying paper
This is the case where the conveyance is normally performed, and FIG. 8 is an example of the case where the retention jam occurs. These will be described with an example of the maximum size that can be designated in the case of copying by the multi-feeder mechanism 2. When paper feed is started by the multi-feeder mechanism 2 in FIG. 6, the main motor is normally rotating as shown in FIG. 7, and the copy paper is sent out by the paper feed roller 2a at the registration rollers 3a and 3b. Stop once. At this time, the jam detection sensor 8 detects the leading edge of the copy sheet. After that, when the optical system starts to move forward, the registration rollers 3a and 3b rotate in synchronization with this and the copy sheet is conveyed. When the copy sheet is conveyed and the toner image is transferred to reach the separation section, the jam detection sensor 9 after separation detects the leading edge of the copy sheet. And
Further, after the trailing edge of the copy sheet has passed the position of the jam detection sensor 8 and the registration rollers 3a and 3b have stopped rotating, a check timing I is issued to the jam detection sensor 8 in front of the registration rollers. In addition, after the sensor 9 detects the trailing edge of the copy sheet, the separated jam detection sensor 9 also outputs a check timing II to the separated jam detection sensor 9. The same applies to the case of the jam detection sensor 10 after the paper discharge rollers 6a and 6b, and the check timing is given by adding + α (hour) to the time corresponding to the length of the copy paper. This is the same in the copying operation for the second and subsequent sheets as shown in FIG. 7, and the copying paper is normally fed and conveyed. In such a case, the jam does not occur.

On the other hand, in the case shown in FIG. 8, when the copy paper longer than the allowable length of the maximum size that can be designated is used, and when the multi-feeder mechanism 2 shown in FIG. Is rotated and the copy paper is sent out by the paper feed roller 2a, and the registration roller 3a is rotated.
And stop at 3b. Also at this time, the jam detecting sensor 8 detects the leading edge of the copy sheet as in the example shown in FIG. Then, when the optical system starts to move forward, the registration rollers 3a and 3b rotate in synchronism with this and the copy sheet is conveyed. When the copy sheet is conveyed and the toner image is transferred to reach the separation section, the jam detection sensor 9 after separation detects the leading edge of the copy sheet. However, since the copy paper is too long, when the check timing I is output to the jam detection sensor 8 in front of the registration rollers, the trailing edge of the copy paper does not pass through and still exists at the position of the jam detection sensor 8. . For this reason, the jam detection sensor 8 detects a stay jam (abnormality) at this point and the main motor stops, and at the same time, the entire copying apparatus becomes inoperable.

[0009]

That is, in the conventional image forming apparatus such as the copying apparatus of this type, when copying is performed by using the multi-feeder mode as described with reference to FIG. The maximum copy paper length is at most the maximum size that can be specified +20 to 30 mm, and copy paper longer than that is surely jammed as described above. As a result, there is a problem in that a sheet longer than the maximum size and longer than the maximum size by about 30 to 40 mm cannot be passed and cannot be copied.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an image forming apparatus having a multi-feeder mechanism that can be used with recording paper longer than an allowable length of a maximum size that can be designated. .

[0011]

In order to achieve the above object, the present invention can use a recording paper longer than the maximum permissible length specified by the multi-feeder mechanism in an image forming apparatus having a multi-feeder mechanism. The purpose is to provide a long manual feed mode. In addition, this image forming apparatus is characterized in that a long manual feed mode key is provided in the operation unit.

Further, in this image forming apparatus, when the image is formed on the recording paper in the long manual feed mode, the sensor provided near the registration roller deactivates the stay jam detecting function and the sensor causes the recording paper to be detected. Is detected, and the timing for jam detection thereafter can be set based on the detected value.

[0013]

According to the above construction, it is possible to use the recording paper longer than the maximum allowable length by utilizing the long manual feed mode of the multi-feeder mechanism.

In particular, since the long manual feed mode key is provided on the operation portion, the long manual feed mode can be used by a simple operation, which is useful when a long recording sheet is used.

When using the long manual feed mode,
The jam detection function of the sensor installed near the registration roller is deactivated, and the length of the recording paper is detected by this sensor and fed back to the control section of the main body of the apparatus, so that the jam detection sensor and subsequent jams can be detected. Since the detection timing can be set, it is possible to appropriately perform jam detection in the separation unit, the paper discharge unit, and the like.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. The same components as those described in the related art are designated by the same reference numerals.

FIG. 1 is a diagram showing the outline of an embodiment of the image forming apparatus of the present invention. This image forming apparatus is an electrophotographic copying apparatus. In FIG. 1, reference numeral 11 denotes a photoconductor made of selenium or the like on which an image is formed. Around the photoconductor 11, a charger 12 for applying a high voltage to the photoconductor 11 to charge the photoconductor 11 and an optical system are provided. Exposure unit (indicated by an arrow) 13 onto which the optical image of the toner is projected, a developing device 14 that visualizes the electrostatic latent image formed by the exposure unit 13, and toner visualized by the developing device 14. Transfer charger 1 that applies a high voltage from the back side when an image is transferred to recording paper (copy paper) P
5, a separation charger 16 that separates the copy sheet P from the photoconductor 11 after transfer, a cleaning device 17 that cleans the residual toner on the photoconductor 11 after transfer, and a discharge lamp 18
Is provided. Further, the above optical system includes a light source lamp 20 for irradiating the original with light, and a reflected light from the original of the photoconductor 11 under the original table 19 on which the original to be copied is placed. First mirror 21 for guiding to the exposure unit 13
a, the second mirror 21b, the third mirror 21c, and the fourth
It is composed of a mirror 21d and a condenser lens 22 provided in the middle of this optical path, and projects an optical image on the exposure unit 13 to form an electrostatic latent image on the photoconductor 11. Further, the light source lamp 20 and the first mirror 21a are arranged on the first mirror base 23, and the second mirror 21b and the third mirror 21c.
Is installed on the second mirror stand 24. The light source lamp 20 and the first mirror 2 arranged on the first mirror base 23
1a starts moving from a home position, which is a reference position, and scans to read an image of a document. A home position sensor 25 for detecting the home position of the first mirror base 23 is provided in the copying machine. Further, a control unit 26 including a microcomputer for controlling the copying apparatus is provided.

The copy paper P is stored in the paper feed cassettes 1A and 1B, and is fed by the paper feed roller 1a or 1b as required. Further, in this embodiment, in addition to the paper feeding by the paper feeding cassette 1, the multi-feeder mechanism 2 is provided so that the copy paper of a desired size can be designated and used according to the user's need. Paper cassette 1
Alternatively, the copy sheet P fed from the multi-feeder mechanism 2 is fed and conveyed by the registration rollers 3a and 3b at the same timing as the image front end of the photoconductor 11 and is conveyed by the transfer charger 15 as described above. A high voltage is applied to the toner image from the photoconductor 11. The copy sheet P having the toner image formed on its surface is separated from the photoconductor 11 by the separation charger 16, and is further conveyed by the transport unit 4.
The toner image is transported by the fixing unit 5, and the toner image is fixed by the fixing unit 5, and is discharged to the paper discharge tray 7 by the paper discharge rollers 6a and 6b. Each of the paper feed cassettes 1A and 1B and the multi-feeder mechanism 2 is provided with sensors Sa, Sb, and Sc for detecting the presence or absence of copy paper P. Further, a jam detection sensor 8, a sensor 9, and a sensor 10 are provided in front of the registration rollers 3a and 3b, after the separation charger 16, and after the paper discharge rollers 6a and 6b.

Further, in this embodiment, when the multi-feeder mechanism 2 is used, a long manual feed mode is provided in which the copy paper P longer than the allowable length of the maximum size that can be designated can be used. Therefore, a long manual feed mode key 28 is provided on the operation unit 27 of this copying machine. FIG. 2 shows the operation unit 2.
It is a figure which shows the outline of 7. In FIG. 2, when the long manual feed mode key 28 is pressed, an LCD (Liquid Crystal Displa
This is displayed on the display unit 29 such as y). Further, in the operation unit 27, the paper selection key 30,
Copy magnification setting key 31 (key 31a is for equal magnification, key 3
1b is for reduction, key 31c is for enlargement), and two zoom memory keys 32 for storing the set copy magnification
a and 32b and a ten key 33 for setting the number of copies are provided, and the items set by these keys are displayed on the display unit 29. The key 34 is a clear key for resetting the number of copies, and the key 35 is a reset key for erasing all the items displayed on the display unit 29 and returning it to the initial state. Further, the operation unit 27 includes a user mode key 36 for specifying a paper size when using the multi-feeder mechanism 2 and a zoom.
A (+) key 37a and a zoom (-) key 37b are provided. In order to specify the paper size, the user mode key 36 is pressed, 5 of the ten keys 33 is pressed, and the user mode key 36 is pressed again to enter the multi-feeder paper size setting mode. Therefore, the display unit 29 changes to the multi-feeder paper size setting mode and the paper size is displayed. FIG. 3 shows the paper sizes sequentially displayed on the display unit 29. When the zoom (+) key 37a is pressed, the display of the paper size is sequentially changed in the direction of the solid line arrow, and when the zoom (-) key 37b is pressed, the display of the paper size is sequentially changed in the direction of the dotted line arrow. Therefore, select the desired paper size using the zoom (+) key 37a or zoom (-) key 37b, and press the user mode key 36 again at the paper size you want to specify, and the multi-feeder will operate with the specified paper size. Will be seen. When the paper size designation in the multi-feeder mechanism 2 is completed in this way, the display unit 29 returns to the mode before the multi-feeder paper size setting mode. Note that the free size in FIG. 3 is substantially the same as when A2 is designated, meaning that any size up to A2, which is the maximum size that can be designated, can be used. The difference is that if the size is specified, the area other than the specified size can be erased, whereas if the free copy is used and a small copy paper is used, the advantage that the frame can be erased disappears. Then, as described in the section of the above-mentioned related art, the jam detection sensor 8, the sensor 9, and the sensor 10 are provided.
The check timing is generated by giving a margin time α of about 20 to 30 mm to the time corresponding to the designated size.

When the copy sheets stored in the cassette and the copy sheets set in the designated size multi-feeder are used, the automatic scaling key 38 is used to automatically change the copy magnification from the relationship between the original and the copy sheets. The frame erase key 39 erases the outside of the frame of the copy paper to be used by irradiating the photoconductor with light. With the frame erasing key 39, the area to be erased can be made larger than that in the case of the designated size. When the binding margin key 40 is desired to be bound at the left end, a desired binding margin can be set with this key 40.
The page continuous shooting key 41 is used when copying in the page continuous shooting mode. Further, the three keys 42a, 42b and 42c are keys for setting the copy density, and the key 42
a is used for automatic exposure, key 42b is used for manually setting a low density, and key 42c is used for manually setting a high density. After the copying conditions are set on the operation unit 27 in this way, the start key 43 is pressed to start the copying operation. If the stop key 44 is pressed when it is desired to interrupt the copying operation, the copying operation thereafter cannot be performed.

When the long manual feed mode in which the multi-feeder mechanism 2 is used and the copy paper P longer than the allowable length of the maximum size that can be specified is used, when the key 28 is pressed as shown in FIG. It is displayed that the mode (a) displayed up to now is the long manual feed mode (b). When the display unit 29 indicates that the long manual feed mode is in effect, the registration rollers 3a and 3b shown in FIG.
The jam detecting sensor 8 in front of is not operated for stay jam detection, and this sensor 8 also serves as a sensor for measuring the length of the copy paper P fed by hand, and the measured detection value is controlled as described above. By feeding back to the unit 26, the check timing for the jam detection sensor 9 and the sensor 10 after the sensor 8 is set based on the detected value. To measure the length of the copy paper P, the control unit 26
The time corresponding to the length of the copy paper P is detected by the system clock (= 2 msec) built in the and the check timing for the jam detection sensor 9 and the sensor 10 after the sensor 8 is set to (the time + β time). To do. In the long manual feed mode, copy sheets P are fed one by one, so continuous copying is not possible. However, the copy magnification is not limited to the uniform magnification (100%) shown in FIG. 4, and the copy magnification can be set by any of the above setting methods. Then, after copying in the long manual feed mode, press key 2 again.
Press 8 to return to the previous mode (a) that was displayed.

Next, using the multi-feeder mechanism 2, the copy paper P longer than the allowable length of the maximum size that can be designated.
The operation / action in the case of making a copy in the long manual feed mode by using will be described with reference to FIG. First, the operator presses the long manual feed mode key 28 of the operation unit 27. Then, the display unit 29 displays the long manual feed mode. When the operator sets the long copy paper P on the multi-feeder mechanism 2, the sensor Sc detects the presence of the copy paper P. Then, when the start key 43 is pressed, the main motor starts rotating. Registration rollers 3a and 3
The jam detecting sensor 8 in front of b is inoperative for detecting jammed jams, and detects the leading edge of the long copy sheet P. The optical system and the photoconductor start moving to project an optical image on the exposure unit 13 to form an electrostatic latent image on the photoconductor 11, and the developing unit 14
To form a toner image. The registration rollers 3a and 3b start rotating in synchronization with the optical system and the photoconductor to convey the long copy sheet P. The jam detection sensor 8 in front of the registration rollers 3a and 3b detects the front end and then the rear end of the long copy paper P, and feeds this back to the control unit 26. Long copy paper P being conveyed
The transfer charger 15 transfers the toner image from the photoconductor, and the separation charger 16 separates the long copy paper P from the transferred photoconductor 11. The jam detection sensor 9 disposed immediately after the separation charger 16 detects the leading edge of the long copy paper P, and then the time corresponding to the length of the long copy paper P detected by the sensor 8 from the control unit 26. Since the check timing II is issued in + β time, when the check timing II comes out, the trailing edge of the long copy sheet P has passed the jam detection sensor 9, and the jam does not occur. The long copy sheet P is further conveyed by the conveying section 4, the toner image is fixed on the fixing section 5, and the sheet is ejected to the sheet ejection tray 7 by the sheet ejection rollers 6a and 6b. Then, the jam detection sensor 10 arranged immediately after the paper discharge rollers 6a and 6b also outputs the check timing at the timing when the jam does not occur. In this way, when the copying of the desired number of long copy sheets P is completed one by one and the key 28 is pressed again, the mode before returning to the long manual feed mode is set and a series of copying operations are completed.

In this long manual feed mode, as in copying using the conventional multi-feeder mechanism, not only the long copy paper P but also a size smaller than the long copy paper P as when a free size of multi-feed is designated. Is also possible with the same operation.

In the above embodiment, the example of the image forming apparatus by the electrophotographic copying apparatus is explained, but the invention is not limited to this. Since the characteristic part of the present invention is that even if a long recording paper is used, the paper is fed and conveyed properly, for example, when an image is read by scanning a document with a CCD or the like and an image is formed. Applicable. It is also applicable to laser printers, ink jet printers that print directly on recording paper, and thermal copying machines.

[0025]

As described above, according to the image forming apparatus of the present invention, the jam detecting sensor is provided with the long manual feed mode in which the recording paper longer than the maximum size that can be designated by the conventional multi-feeder mechanism can be used. Control so that the jam detection check timing is output.
It becomes possible to use a recording paper having a maximum size that is larger than the maximum size that can be specified in the related art.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of an embodiment of an image forming apparatus of the present invention.

FIG. 2 is a diagram for explaining an operation unit.

FIG. 3 is a diagram showing a method of specifying a paper size in a multi-feeder mechanism.

FIG. 4 is a diagram showing a display method when a long manual feed mode is used.

FIG. 5 is a diagram showing a timing chart when a long manual feed mode is used.

FIG. 6 is a diagram for explaining a conventional paper feeding / conveying mechanism.

FIG. 7 is a diagram showing a timing chart of conventional paper feed / conveyance control.

FIG. 8 is a diagram illustrating a conventional timing chart of sheet feeding / conveying.

[Explanation of symbols]

 1 Paper Feed Cassette 2 Multi-Feeder Mechanism 3 Registration Roller 4 Conveying Section 5 Fixing Section 6 Paper Ejection Roller 7 Paper Ejection Tray 8 Jam Detection Sensor 9 Jam Detection Sensor 10 Jam Detection Sensor 11 Photosensitive Body 12 Charger 13 Exposure Section 14 Developing device 15 Transfer charger 16 Separation charger 17 Cleaning device 18 Discharge lamp 19 Document table 20 Light source lamp 21 Mirror 22 Condensing lens 23 First mirror table 24 Second mirror table 25 Home position sensor 26 Control section 27 Operating section 28 Long Manual feed mode key 29 Display 36 User mode key 37 Zoom key

Claims (3)

[Claims] 1. An image forming apparatus having a multi-feeder mechanism, characterized in that a long manual feed mode capable of using a recording paper longer than an allowable length of a maximum size that can be designated by the multi-feeder mechanism is provided. . 2. The image forming apparatus according to claim 1, wherein a long manual feed mode key is provided on the operation unit of the image forming apparatus. 3. The image forming apparatus according to claim 1 or 2, wherein when the image is formed on the recording paper in the long manual feed mode, the sensor provided near the registration roller is made inoperative to detect the stay jam and the image is recorded by the sensor. Detects the length of the paper,
An image forming apparatus capable of setting a timing for jam detection thereafter based on the detected value.