JP2002326763A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of correctly detecting overloading on a sheet stacking means without adding special devices. SOLUTION: A tray load weight determining means 705 refers to load weight data Mi for a bin tray Bi as a destination of delivery from a load weight data table for each bin tray stored in a RAM in this image forming device, and it selects weight data M0 for a sheet being image-formed from a weight sorting table. Load weight data Mi' as the load weight data Mi referred to added by the sheet weight data M0 is compared with limit load weight data Mmax for the bin tray Bi, thereby overloading is determined.

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 provided with sheet placement means such as a sorter for loading sheets on which images are formed.

[0002]

2. Description of the Related Art Conventionally, as this type of image forming apparatus,
For example, sheets formed by an image forming unit based on a document automatically fed by an automatic document feeder are collated and sorted into a plurality of bin trays of a sheet processing apparatus connected downstream, and stacked. A configuration is known in which post-processing such as stapling and punching is performed by post-processing means.

When sheets are discharged to the bin tray, placing sheets on the processing apparatus that exceeds the storage capacity of the sheet processing apparatus may cause a failure of the sheet processing apparatus. At this point, a process for limiting the stacking on the sheet processing apparatus is performed. In this stacking restriction process, it is common to determine the excess of stacking by counting the number of sheets discharged onto the bin tray.

[0004]

In the above-described apparatus, when the originals loaded on the original placing table of the automatic original feeder are in the mixed mode including originals of different sizes, each time the originals are fed. After the document size is detected by the size detecting means, a sheet of the same size for recording (for image formation) is fed. In this case, sheets of various sizes are mixedly loaded on the bin tray of the sheet processing apparatus.

[0005] Further, even when originals of different sizes are continuously copied while leaving the discharged sheets in the bin tray of the sheet processing apparatus, sheets of different sizes are mixed in the bin tray of the sheet processing apparatus. Will be loaded.

In the conventional stacking restriction process, the excess stack is determined by managing the number of discharged sheets. Therefore, when the discharged sheets are of the same type and the same size, the excess stack can be correctly determined. However, when sheets of different or different sizes are mixedly loaded as described above, an error occurs between the loaded weight calculated from the number of discharged sheets and the actual loaded weight. Therefore, conventionally, when sheets are mixed, a method of limiting the number of sheets to be stacked in accordance with the sheet having the smallest number of sheets among the sheets, or the load on the sheet processing apparatus is the least. Either of the methods of unifying the maximum number of sheets that can be stacked to a smaller size regardless of the sheet type and size is adopted.

[0007] For example, if the limit number of bin trays is A4
In the case of an image forming apparatus in which the number of sheets is 40 and the number of A3 sheets is 20, in the former method, when one A3 sheet is first discharged to the bin tray, the number of A3 sheets is counted thereafter. Therefore, even when A4 sheets are subsequently discharged, the stacking is restricted when 19 sheets are discharged.

In the latter method, for example, the limit of the number of sheets of other types and sizes is set to 20 in accordance with the limit of the number of sheets of A3, for example. In other words, loading is limited at half of the number of sheets that can be loaded originally.

As described above, in the prior art, when the output originals are mixed, the sheets must be removed before the stacking limit of the bin tray, and when processing a large number of sheets, the frequency of the user removing the sheets from the tray increases. There was a problem that productivity was reduced.

As a solution to such a problem, it is conceivable to provide a weight sensor on each bin tray in order to accurately know the stacking limit of the sheet processing apparatus. However, adding a new apparatus increases the size of the apparatus. It is not preferable because it leads to cost increase.

The present invention has been made in view of the above circumstances, and an object of the present invention is to enable accurate detection of an excess load of a sheet placing means without adding a special device. An object of the present invention is to provide an image forming apparatus.

[0012]

According to the present invention, there is provided an image forming means for forming an image on a sheet, and a sheet discharging means for discharging the sheet on which the image is formed by the image forming means. Means, and sheet mounting means for stacking the sheets discharged by the sheet discharging means, the weight information of the sheet on which an image is being formed and the sheets already stacked on the sheet mounting means. The present invention is characterized in that there is provided an overload judging means for judging an overload of the sheet mounting means based on the accumulated weight information.

Here, the term "sheet during image formation" includes not only a sheet on which an image is actually formed by the image forming means but also a sheet on which an image is to be formed by the image forming means. The sheet includes, for example, a sheet that is being conveyed toward the image forming unit or a sheet that is to be conveyed, and a sheet that has undergone image formation and is subjected to discharge / stacking processing.

The overload determination means includes storage means for storing load limit weight information, which is the maximum load capacity of the sheet placement means, and cumulative weight information of sheets already loaded on the sheet placement means, and the storage means. Calculating means for adding the weight information of the sheet on which an image is being formed to the accumulated weight information stored in the storage means; comparing means for comparing the calculation result of the calculating means with the load limit weight information stored in the storage means; And an excess load detecting means for detecting an excess load of the sheet placing means based on a comparison result of the comparing means.

Preferably, the excess load judging means selects weight information corresponding to the sheet on which an image is being formed from a weight information group pre-classified according to the type or size of the sheet.

Here, the term "sheet" refers to a transfer paper, a photosensitive paper, a thermal paper, a transfer paper to be supplied to an apparatus in office equipment such as a copying machine, a printer, a printing machine, a facsimile, and other various equipment using sheets. Refers to all sheets (cut sheets) such as electrostatic recording paper, printing paper, originals, cards, and envelopes. The material is not limited to paper, but includes, for example, a film material such as an OHP sheet.

The term "sheet type" refers to transfer paper, photosensitive paper, thermal paper, electrostatic recording paper, printing paper, manuscript, card, envelope, thickness, weighing, material, material characteristics, sheet, etc. Includes manufacturers and products.

Stop means for stopping the image forming operation when the excess load determination means determines that the load is excessive, and warns the user of the excess load when the excess load determination means determines that the load is excessive. Load warning means.

A plurality of the sheet placement means are provided, and the excess stack determination means includes information on the weight of the sheet during image formation and the accumulated weight of the sheet placement means serving as a discharge destination of the sheet among the plurality of sheet placement means. It is characterized by judging, based on the information, the excess of the sheet placement means.

It is preferable that a plurality of image forming modes are provided, and the stopping means changes the stop timing of image formation in accordance with the image forming mode.

The image forming mode includes a sort mode for collating sheets in the order of pages and sorting the sheets into a plurality of sheet placing units when preparing a plurality of copies of an image composed of a plurality of pages. In the case of the sorting mode, when it is determined that the stacking is excessive, the image forming operation may be stopped after all the images of the page are created.

The overload warning means may warn of overload by displaying a message or lighting a lamp.

A sheet presence / absence sensor for detecting whether or not sheets are loaded on the sheet loading means is provided, and the excess loading determination means detects that a sheet has been removed from the sheet loading means by the sheet presence / absence sensor. At this time, the accumulated weight information of the sheet stacking means may be reset.

The overload warning means may release the overload warning when the sheet presence sensor detects that the sheet has been removed from the sheet loading means.

[0025]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the present embodiment, an explanation will be given by taking an electrophotographic color image forming apparatus as an example.
The present invention can be suitably applied to a monochrome copying machine, a printer, an image forming apparatus of an ink jet system, and the like.

FIG. 1 is a schematic sectional view of the configuration of an image forming apparatus according to the present embodiment. The color image forming apparatus has a color reader unit 1 at an upper part and a color printer unit 2 at a lower part,
The sheet on which an image is formed by the color printer unit 2 is discharged by a sheet discharge roller 57 to a sheet post-processing device 4 shown in FIG.
00 and is subjected to post-processing.

[Structure of Color Reader Unit] In FIG.
Platen glass (platen) on top of color reader unit 1
A document feeder (DF) 12 is provided on the horizontal side.
Is installed. There is also a configuration in which a mirror surface pressure plate is mounted instead of the document feeder 12. Inside the color reader unit 1, first and second carriages 13 and 19 are arranged. In the first carriage 13, light sources 14 and 15 composed of halogen lamps, and light from these light sources 14 and 15 are transmitted to a document. And mirrors 18 for reflecting the reflected light or the projected light from the original. Further, mirrors 20 and 21 for condensing the reflected light from the mirror 18 on the CCD 24 are mounted on the second carriage 19.

The first carriage 13 is driven at a speed V, and the second carriage 19 is driven at a speed V / 2, in the direction perpendicular to the electrical scanning (main scanning) direction of the CCD 24, and the driving means 25.
The entire surface of the document is scanned (sub-scan) by mechanically moving the document.

The original on the platen glass 11 is a light source 14,1.
5 is reflected, and the reflected light is guided to the CCD 24 and converted into an electric signal. In the case where the CCD 24 is a color sensor, even if the RGB color filters are mounted in-line on a one-line CCD in the order of RGB, the CCD 24 may be a three-line CCD.
In the case of a CD, an R filter, a G filter, and a B filter may be arranged for each CCD.
The filter may be on-chip or the filter may have a different structure from the CCD.

The color reader 1 further includes a substrate 23 on which the above-described CCD 24 is mounted, and a CCD 2 shown in FIG.
4, an image processing unit 26 including the binary conversion unit 301, the delay units 303Y to 303K shown in FIG. 3, and an interface (I / F) unit 27 with another IPU or the like.

FIG. 2 is a block diagram showing a detailed configuration of the digital image processing section 26.

The electric signal (analog image signal) input to the CCD 24 by the above-described document scanning is clamped
mp. The sample / hold (S / H) is performed by the & S / H & A / D unit 201, the dark level of the analog image signal is clamped to the reference potential, and is amplified to a predetermined amount (the processing order is not limited to the notation order). D-converted, for example, R
It is converted into a digital signal of 8 bits for each GB.

The RGB signals are subjected to shading correction and black correction by the shading unit 203,
It is input to the connection & MTF correction & original detection unit 205.

The connection & MTF correction & original detection unit 205 corrects the reading position timing. When the CCD 24 is a three-line CCD, the reading positions between the lines are different. Therefore, the signal timing is corrected so that the reading positions of the three lines become the same by adjusting the delay amount for each line in accordance with the reading speed by the connecting process. In addition, since the reading MTF changes depending on the reading speed and the magnification, the change is corrected by the MTF correction, and the platen glass 11 is corrected by the document detecting process.
Recognize the upper document size.

The digital signal whose reading position timing has been corrected is input to the CCD 24 by the input masking unit 207.
And the spectral characteristics of the light sources 14 and 15 and the reflectors 16 and 17 are corrected. The output of the input masking unit 207 is input to a selector 209 that can be switched to an external I / F signal.

The signal output from the selector 209 is input to a color space compression & background removal & LOG conversion unit 211 and a background removal unit 225. After the signal input to the background removal unit 225 is removed from the background, the signal is input to a black character determination unit 227 that determines whether or not the document is a black character in the document, and a black character signal is generated from the document. Also, another selector 2
09 color space compression & background removal & LOG input
The conversion unit 211 determines in the color space compression process whether the read image signal is within the range that can be reproduced by the printer. If the image signal is included, it is left as it is. If not, the image signal can be reproduced by the printer. Correct so that it falls within the range. Then, a background removal process is performed, and the RGB signals are converted into CMY signals by LOG conversion.

To correct the signal and timing generated by the black character determination unit 227, color space compression, background removal, and LO
The timing of the output signal of the G conversion unit 211 is adjusted by the delay circuit 213. These two types of signals are supplied to the moire removing unit 21.
In step 5, the moire is removed, and then the magnification processing section 217 performs magnification processing in the main scanning direction.

The CMYK signal is generated from the CMY signal by the UCR process, the signal subjected to the scaling process by the scaling process unit 217 is corrected by the masking process unit into the signal output from the printer, and the black character determination unit 227 is used. Is fed back to the CMYK signal.

UCR & Masking & Black Character Reflection Unit 219
Is subjected to density adjustment by the γ correction unit 221, and then subjected to smoothing or edge processing by the filter unit 223.

The signal processed as described above is converted from an 8-bit multi-level signal into a binary signal by a binary converter 301 shown in FIG. This conversion method may be any one of the dither method, the error diffusion method, and an improved version of the error diffusion method.

[Configuration of Color Printer Unit] In FIG. 1, a Y image forming unit 30Y, an M image forming unit 30M, a C image forming unit 30C, and a K image forming unit 30K include a photosensitive drum 31, a charger 32, and an LED, respectively. Part 33, developing device 34,
An auxiliary charger 35 is provided. The charger 32 has a charging sleeve 36, and the developing device 34 has a developing sleeve 37.

Since the respective structures are the same, the Y image forming unit 30Y will be described in detail, and the description of the other image forming units will be omitted.

The Y image forming section 30Y includes a photosensitive drum 31
, And a charger 32, an LED unit 33, a developing device 34, an auxiliary charger 35, and the like are disposed therearound.

In these operations, first, the photosensitive drum is charged by the auxiliary charger 35 and the charger 32. Charger 32
By rotating the charging sleeve 36 in the direction opposite to that of the photosensitive drum 31, a ferrite carrier 38 having a low resistance can be obtained.
To form a dielectric brush to uniformly charge the surface of the photosensitive drum 31 to prepare for latent image formation.

Next, by irradiating light from the LED section 33, an electrostatic latent image is formed on the surface of the photosensitive drum 31, and the latent image is developed by a developing device 34 using a yellow developer. The latent image is visualized as a yellow toner image. The developing device 34 has a developing sleeve 37, carries a developer on the developing sleeve 37, conveys the developer to the photosensitive drum 31, and develops a latent image while applying a developing bias to the developing sleeve 37.

A transfer charger (transfer roller) is provided below the photosensitive drum 31 with a transfer belt 40 serving as a recording material conveying member interposed therebetween.
The transfer charger 39 transfers the transfer belt 40.
To discharge the yellow toner image on the photosensitive drum 31 onto a recording material such as paper conveyed while being carried on the transfer belt 40.

After this transfer, the toner remaining on the photosensitive drum 31 is once taken into the charger 32, the charging polarity is changed by friction with the carrier, and the toner is returned to the photosensitive drum 31 again. And reuse.

Next, a procedure for forming an image on a recording paper or the like will be described. The recording paper and the like stored in the cassettes 42 and 43 are taken out one by one by the pickup rollers 44 and 45 and supplied onto the transfer belt 40 moved by the registration roller pairs 46 and 47.

The transfer belt 40 includes a Y image forming unit 30Y,
1 is disposed below the M image forming unit 30M, the C image forming unit 30C, and the K image forming unit 30K, is wound around a plurality of rollers such as a driving roller 48, and is driven by the driving roller 48 in FIG.
The endless moving body rotates counterclockwise.

The leading edge of the recording paper fed to the transfer belt 40 is detected by a paper leading edge sensor 51. The detection signal of the paper leading edge sensor 51 is sent from the color printer unit 2 to the color reader unit 1 and is used as a sub-scan synchronization signal when a video signal is sent from the color reader unit 1 to the color printer unit 2.

Thereafter, the recording paper or the like is conveyed by the transfer belt 40, and the image forming units 30Y, 30M, 30C, 3
At 0K, a toner image is formed on the surface in the order of YMCK.

The recording paper or the like that has passed through the K image forming section 30K is separated from the transfer belt 40 after being discharged by a discharging charger 52 in order to facilitate separation from the transfer belt 40. A peeling charger 53 is provided adjacent to the static eliminator 52 to prevent image disturbance due to peeling discharge when the recording paper or the like is separated from the transfer belt 40.

The separated recording paper or the like is charged with pre-fixing chargers 54, 5 in order to compensate for the toner attraction force and prevent image disturbance.
After being charged in 5, the toner image is heat-fixed by a fixing device 56, and is discharged to a sheet post-processing device by a discharge roller 57 serving as a sheet discharging means. The transfer belt 40 is neutralized by the internal and external static eliminators 58 and 59.

Next, the LED image recording will be described with reference to FIG. In FIG. 3, a signal from an image processing unit is binarized by a binary conversion unit 301, and delay units 303Y to 303Y.
Input to 3K. YM in delay units 303Y to 303K
Each image data of CK is delayed and output according to the distance between the paper leading edge sensor 51 and each of the image forming units 30Y to 30K.

The image data output from the delay units 303Y to 303K is sent to the LED driving units 305Y to 305K. The LED driving units 305Y to 305K have a plurality of shift registers that latch and hold input image data for each predetermined image data, and the image data for one line is held at the timing when these shift registers hold the image data. A signal for driving the LED units 33Y to 33K is generated based on the data.

[Structure of Sheet Post-Processing Apparatus] FIGS.
FIG. 2 is a diagram illustrating a detailed configuration of a sheet post-processing apparatus shown in FIG. 1. FIG. 4 is a schematic sectional view of the configuration of the sheet post-processing apparatus according to the present embodiment, and FIG. 6 is a schematic perspective view of the sheet post-processing apparatus. FIG. 5 is a schematic perspective view of a bin unit provided in the sheet post-processing apparatus.

As shown in these figures, the sheet post-processing apparatus 400 includes a body 402 and a bin unit 403.
The body 402 is provided with a carry-in roller pair 405 in the vicinity of the carrying port 404. A flapper 409 that switches the sheet conveyance direction to a conveyance path 406 or a conveyance path 407 is provided downstream of the carry-in roller pair 405.

One of the transport paths 406 extends substantially in the horizontal direction, and a transport roller pair 408 is disposed downstream of the transport path 406. The other transport path 407 extends in the downward direction.
A transport roller pair 411 is disposed downstream of the stapler 412.
a, 412b. The carry-in roller pair 405 and the carry roller pairs 408 and 411 are driven by a carry motor (not shown). In the transport path 406,
Non-sort path sensor S401 that detects passage of a sheet
And the transport path 407 has a sort path sensor S40.
2 are provided.

A bin unit 403 is disposed downstream of the pair of conveying rollers 408 and 411. The bin unit 403 includes a large number of bin trays B as sheet stacking means for stacking sheets, and one end of the bin unit 403 is engaged with a hook of the bin unit 403.
The weight is held by a spring whose other end is fixed to the body 402,
It is supported to be able to move up and down with respect to the body 402.

The base end side of the bin unit 403 (body 402
Guide rollers 417, 419 are rotatably provided above and below the side. These guide rollers 417 and 419
Rolls in a guide groove 420 provided in the body 402 so as to extend in the vertical direction, and the bin unit 403
Is configured to be guided. Further, a shift motor 421 is provided on the body 402. A lead cam 423 and a sprocket 425 are fixed to a rotating shaft 422 pivotally supported by the body 402. A chain 426 is stretched between the sprocket 425 and the output shaft of the shift motor 421.
The rotation of 21 is transmitted to a rotation shaft 422 via a chain 426.

Further, the bin unit 403 includes a bottom frame 427 having an inclined portion and a vertical portion, a pair of frames 429 provided vertically on the front and rear sides of the bottom of the bottom frame 427, and the frame 429. It has a unit main body 431 composed of a supported cover 430.

The lower arm 4 which is rotated by the alignment motor 432a is located on the back side of the base end of the bottom frame 427.
33a is rotatably supported (see FIG. 5). Further, an upper arm 435a is fixed to a shaft 436a rotatably supported by the cover 430 at a position facing the lower arm 433a of the cover 430, and the center of rotation of the upper arm 435a and the lower arm 435a. A shaft is provided at the center of rotation of 433a.

An alignment rod 439a is provided between the distal end of the lower arm 433a and the distal end of the upper arm 435a. The alignment rod 439a is configured to rotate by an alignment motor 432a. The upper sheet is aligned in the width direction (front side in the figure).

The matching motor 432a is constituted by a stepping motor, and the position of the matching rod 439a can be accurately controlled by the number of pulses applied to the stepping motor. S403a is a matching rod home sensor for detecting the position of the matching rod 439a.
Are aligned with the alignment bar home sensor S403a and the alignment motor 4
It is controlled by the number of pulses given to 32a.

The bin tray B has a predetermined distance from the shaft that is longer than the rotation distance of the alignment rod 439a, and
An elongated hole 443a that is sufficiently wider than the width a is opened.

The base end Ba of the bin tray B rises perpendicularly to the sheet storage surface Bb. The bin tray B has a tip inclined upward at a predetermined angle with respect to the body 402,
Due to this inclination, the sheet discharged to the bin tray B slides on the sheet storage surface Bb and abuts the rear end against the base end Ba to be aligned in the front-rear direction.

The bin tray B has a stapler 412
The notches BC1 and BC2 are provided at the portions where the a and 412b enter, so that they do not interfere with the stapler 412. Then, the long holes 44 of the bin trays B1 to Bn
An alignment bar 439a is inserted into 3a, and is configured to rotate in the elongated hole 443a to align the sheet on the bin tray B to the near side.

Rollers 442 are provided at both ends of the base end portion Ba of the bin tray B. The roller 442 engages with a spiral groove 423a (see FIG. 6) formed on the outer peripheral surface of the lead cam 423, and moves up and down by rotation of the lead cam 423. As a result, the bin tray B moves up and down along the guide grooves provided to extend vertically in the frame.

Note that one rotation of the lead cam 423 is performed by the lead cam sensor S40 provided near the lead cam 423.
4 detected. The position of the bin unit 403 is detected by the bin home position S405.

Each of the bin trays B1 to Bn is provided with a sheet presence / absence sensor S407 for detecting whether or not sheets are stacked.

The electric stapler 412a, 412b, which is disposed near the pair of conveying rollers 411 and binds the sheets stored in the bin tray B, is disposed at a position orthogonal to the sheet carrying direction so as to be able to advance and retreat by driving means. In order to prevent interference when the bin tray B is moved up and down, the bin B is retracted to the position A, and when binding a bundle of sheets on the bin tray B, the sheet is moved to position B to bind the sheet bundle. After completion of the stapling, the staplers 412a and 412b return to the position A by a driving unit (not shown). Further, the staplers 412a and 412b are moved up and down by rotation of a motor (not shown) to bind the sheet bundles stacked on the bin trays B1 to Bn. S406 in FIG. 6 is a manual stapling key. When the manual stapling key S406 is pressed after sorting is completed, a stapling operation is performed.

Next, the sheet discharging operation in the image forming apparatus having the above configuration will be described.

FIG. 7 is a functional block diagram showing main functions in sheet processing of the image forming apparatus according to the present embodiment. The function of each unit in the figure is realized by executing a program stored in a ROM in the image forming apparatus.

The operation mode selection means 701 is configured on an operation unit attached to the image forming apparatus, and selects an image forming mode to be performed later by the user. When the sort, group, and staple modes are selected by the operation mode selection unit 701, or when a mode for discharging paper to the sort bin is selected, the sheet is discharged to the bin tray.

The sort mode is a mode in which sheets are collated and sorted into a plurality of bin trays in the order of pages when an image (original) composed of a plurality of pages is created (copied) in a plurality of copies. The group mode is a mode in which pages are sorted into a plurality of bin trays for each page. When the staple mode is selected, the sheets sorted on the respective bin trays are bound.

The image formation start means 702 is constituted by an image formation start key provided on the operation section, and the image formation is started when the image formation start key is pressed.

Upon receiving a start command from the image forming start means 702, the image forming section 703 starts an image forming operation.

At the same time, in response to the start command, the discharge bin tray determining means 704 is activated for each sheet on which an image is to be formed. The paper discharge bin tray determining means 704 determines whether or not each sheet is a paper discharge mode to the bin tray based on the image forming mode selected by the operation mode selection means 701, and in the case of the paper discharge mode to the bin tray, the bin tray B1 ＢBn to be discharged will be determined.

Tray loading weight calculation means (calculation means) 70
Reference numeral 5 stores the loaded weight data (cumulative weight information) M1 to Mn of the sheets already loaded on the bin trays B1 to Bn in the RAM (storage means) of the image forming apparatus. Then, a bin tray Bi when an image formation-scheduled or image-forming sheet is discharged to the bin tray Bi determined as a discharge destination by the discharge bin tray determination means 704.
Is calculated.

In this embodiment, the calculation of the load applied to the bin tray is simplified by classifying and encoding the sheet weight into four types based on the area and the weighing. Area is A
4 Small less size, two types of larger sheet than A4 size as large, weighing treats in two kinds of plain paper less than 105 g / m ^3, more than a thick, area, four kinds of combinations of the weighing Seat weight category. Then, for each weight category, weight data (weight information) is set which encodes the weight such as 1 for small-sized plain paper, 2 for large-sized plain paper and small-sized thick paper, and 4 for large-sized thick paper.

The limit weight storage means 706 stores the limit weight that can be discharged to one bin tray in the RAM of the image forming apparatus. The load limit weight data (load limit weight information) Mmax is also handled by data encoded in the same manner as the above-mentioned seat weight data. In the present embodiment, the load limit weight data Mmax is set to 40.

The comparing means 707 compares the loading weight data Mi of the bin tray Bi calculated by the tray loading weight calculating means 705 with the loading limit weight data Mmax stored and held by the loading limit weight storage means 706.
“Loading weight data Mi ≧ loading limit weight data Mmax”
Is determined to be over the loading limit. Therefore, in the present embodiment, when the above-described four types of sheets are discharged without being mixed, 40 sheets of small-sized plain paper, 20 sheets of large-sized plain paper and small-sized thick paper, and 10 sheets of large-sized thick paper It is determined that the stacking limit has been exceeded when the sheet is discharged.

When the comparison means 707 determines that the load limit is over, the load limit over setting means (load excess detection means) 708 sets the load limit over. However, in the present embodiment, considering the convenience of the user, depending on the mode selected by the operation mode selection unit 701, the comparison unit 70 may be used.
7, even if it is determined that the stacking limit is exceeded, the setting of the stacking limit is not immediately performed, and the image formation is continued until a certain point in time. For example, when the sorting mode is designated, when it is determined that the stacking limit is exceeded, the setting of the stacking limit is set when the image formation of all the images of the page is completed.

When the overload limit is set, the image formation stopping means 709 performs image formation stop processing on the image forming section 703, and an image is formed on the sheet determined to be overload, and the sheet is discharged. At this point, the operation of the image forming unit is stopped.

The bin tray driving device 710 is configured to discharge the image-formed sheet to the bin tray Bi based on the determination of the discharge bin tray determining means 704.
i is raised and lowered to a specified position. Then, the sheet discharging device 711 discharges the sheet to the bin tray Bi moved to the discharging portion by the bin tray driving device 710.

When a sheet is discharged to the bin tray, the sheet discharge sensor 712 outputs a detection signal, and the CPU of the image forming apparatus receives the output signal from the sheet discharge sensor 712 so that the CPU normally operates after image formation. Check that the sheet has been discharged to the bin tray. If the image forming operation is interrupted before the image forming apparatus completes the image formation for all the originals (no paper, no toner, jam, etc.), the sheet discharge sensor 712 is used.
The loaded weight data of each bin tray included in the tray loaded weight calculation means 705 is corrected based on the counter value (which is stored and held in the RAM of the image forming apparatus) which counts the detection signal of (1).

When the sheet on which the image is formed is normally discharged and the operation of the image forming unit is stopped, and the setting of overload limit is set by the overload limit setting means 708, a load limit alarm is generated. Means (load excess warning means) 713 notifies the user that the limit load on the bin tray has been exceeded (in the present embodiment, a message is displayed on the operation unit and an alarm lamp is lit).

The sheet presence sensor 714 (S40 in FIG. 5)
7) is a sensor for monitoring the presence or absence of a sheet on the bin tray. In the present embodiment, the presence or absence of the sheet on the bin tray is determined using a set of light transmission sensors. The sheet presence sensor 714 includes bin trays B1 to B1.
At the time when all the sheets of Bn have been removed, the absence of paper on the bin tray is detected, and upon receiving the detection signal, the loaded weight resetting means 715 outputs the loaded weight data of the bin trays B1 to Bn of the tray loaded weight calculating means 705. Reset to "0".

Next, using the sort mode as an example, a description will be given in detail of the determination of the excess of the loaded weight during image formation in the present embodiment with reference to the flowchart of FIG.

In step S801, image formation is started by pressing an image formation start key provided on the operation unit of the image forming apparatus.

Next, in step S802, the discharge bin tray determining means 704 determines the output bin tray based on the operation mode.
The discharge bin tray Bi is determined.

In step S803, it is first determined whether or not the overload flag is set. The loaded weight excess flag is a flag set in the following step S804, and is not set in the initial state.

If the flag is set, it means that there is a paper discharge bin tray for which the stacking weight excess has already been determined other than the paper discharge bin tray Bi, and the process proceeds to step S806. On the other hand, when the loaded weight over flag is not set, the tray loaded weight calculation means 705 calculates the load applied to the discharge bin tray Bi.

The tray loading weight calculating means 705 reads the loading weight data of the bin tray Bi as the discharge destination from the loading weight data table of each bin tray B1 to Bn as shown in FIG. 9 stored in the RAM in the image forming apparatus. With reference to Mi, the weight data M0 of the sheet to be image-formed or under image formation is selected from a weight classification table classified by sheet size and sheet type as shown in FIG. The sum of the referenced load weight data Mi and seat weight data M0 is stored as new load weight data Mi 'in the load weight data table. Next, the comparing means 707 compares the new load weight data Mi 'with the load limit weight data Mmax, and if Mi' ≧ Mmax, determines that the bin tray Bi is over the load weight. Set the over flag.

In the present embodiment, in the sort mode, even if one bin tray is determined to be over the stacking weight, the same document is ejected for the number of copies and then stopped. Then, it is determined whether or not the image formation of the same document has been completed. If image formation on the same document has not been completed, the process proceeds to step S802 to start image formation on the next sheet. If the image formation for the same document on the current sheet is completed, the process proceeds to step S807, and the image forming apparatus is stopped.

On the other hand, if it is determined in step S803 that the output bin tray does not exceed the stacking weight, it is determined in step S806 whether or not image formation has been performed on all the originals. Until the image formation is completed, the operation for judging the excess of the loaded weight is repeated.

If the sheet discharge sensor 712 detects that all the sheets to be discharged have been discharged after the stop processing in step S807, the stacking weight excess flag is set in step S808. It is determined whether or not the load limit is exceeded, and if it is determined that the load limit is exceeded, the load limit alarm generating means 713 is executed in step S809, and the load limit weight of the bin tray is exceeded for the user. Is notified.

The stacking limit alarm is reset when the sheet presence / absence sensor 714 detects that all sheets in the discharge bin tray have been removed. When the image forming operation is interrupted due to the excess of the loaded weight, the image forming operation is restarted after removing the sheet. When the image forming operation is restarted, the pressing of the image forming start key may be detected again, or the image forming operation may be automatically restarted when the sheet is removed. Also,
If it is determined that the stacking weight is exceeded, but the image forming operation for all the originals has been completed, the operation unit screen is returned to the initial state when the removal of the sheet is detected.

As described above, according to the present embodiment,
Sheet weight data M0 during image formation (to be formed)
Is determined based on the loaded weight data Mi of the sheets already loaded on the bin tray Bi to which the sheets are discharged, so that sheets of various sizes and types are mixedly loaded. In this case as well, it is possible to accurately detect excess sheet loading. In addition, in realizing the above-described processing, it is not necessary to add a special device such as a weight sensor, so that an increase in the size and cost of the device is not caused.

Also, by categorizing and encoding the weight of the sheet in advance according to the type and size of the sheet,
The above arithmetic processing can be simplified. In the present embodiment, four types are classified according to the weighing and the size. However, it is needless to say that the sheet stacking amount can be more accurately obtained by further subdividing.

Further, in the present embodiment, when the sort mode is selected, the image forming operation is continued until all the pages judged to be overloaded are created, so that the same page is stored in each bin tray. Since the number of sheets is outputted, the handling when aligning the sheet bundle output halfway with the sheet bundle output after removing them becomes easy.

In the present embodiment, when it is determined that the stacking weight is over, the overload alarm is notified even when the image forming operation for all the originals is completed. If the image forming operation for the document has been completed, the alarm is not notified after the completion, and the sheet weight remains when the job using the output bin tray is selected again with sheets remaining in the output bin tray. It may be configured to notify an over-alarm.

[0103]

As described above, according to the present invention, based on the weight information of the sheet on which the image is being formed and the accumulated weight information of the sheets already loaded on the sheet placing means, the excess of the sheet placing means is determined. Judgment makes it possible to calculate the weight load applied to the sheet placing means without any additional equipment, and to accurately detect the excess of the sheet placing means, thereby improving the efficiency of image formation and operability. Can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration sectional view of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a digital image processing unit of the image forming apparatus of FIG. 1;

FIG. 3 is a block diagram illustrating a configuration of an LED driving unit of the image forming apparatus of FIG. 1;

FIG. 4 is a schematic configuration sectional view of a sheet post-processing apparatus according to an embodiment of the present invention.

FIG. 5 is a schematic perspective view of a bin unit provided in the sheet post-processing apparatus of FIG.

FIG. 6 is a schematic perspective view of the sheet post-processing apparatus of FIG.

FIG. 7 is a functional block diagram relating to a sheet processing operation in the image forming apparatus of FIG. 1;

FIG. 8 is a flowchart relating to a sheet processing operation in the image forming apparatus of FIG. 1;

FIG. 9 is an example of a loaded weight data table of each bin tray.

FIG. 10 is an example of a seat weight classification table.

[Explanation of symbols]

Reference Signs List 1 color reader section 2 color printer section 11 platen glass 12 document feeder 13 carriage 14, 15 light source 16, 17 reflector 18 mirror 19 carriage 20, 21 mirror 23 substrate 24 CCD 25 driving means 26 (digital) image processing section 27 Interface (I / F) Unit 30Y, 30M, 30C, 30K Image Forming Unit 31 Photosensitive Drum 32 Charger 33, 33Y, 33M, 33C, 33K LED Unit 34 Developing Unit 35 Auxiliary Charging Unit 36 Charging Sleeve 37 Developing Sleeve 38 Ferrite Carrier 39 Transfer charger 40 Transfer belt 42, 43 Cassette 44, 45 Pickup roller 46, 47 Registration roller pair 48 Driving roller 51 Paper leading edge sensor 52 Static elimination charger 53 Peeling charger 54, 55 Pre-fixing charger 56 Fixing unit 57 Paper rollers 58 and 59 a static eliminator 201 clamp & Amp. & S / H & A / D section 203 Shading section 205 Bridge & MTF correction & Original detection section 207 Input masking section 209 Selector 211 Color space compression & background removal & LOG conversion section 213 Delay circuit 215 Moiré removal section 217 Magnification processing section 219 UCR & Masking & Black text Reflection unit 221 Gamma correction unit 223 Filter unit 225 Background removal unit 227 Black character determination unit 301 Binary conversion unit 303Y, 303M, 303C, 303K Delay unit 305Y, 305M, 305C, 305K LED drive unit 400 Sheet post-processing device 402 Body 403 bin Unit 404 Transport port 405 Loading roller pair 406, 407 Transport path 408 Transport roller pair 409 Flapper 411 Transport roller pair 412, 412a, 412b (Electric) stapler 417, 419 L 420 Guide groove 421 Shift motor 422 Rotating shaft 423 Lead cam 423a Spiral groove of lead cam 425 Sprocket 426 Chain 427 Bottom frame 429 Frame 430 Cover 431 Unit main body 432a Alignment motor 433a Lower arm 435a Upper arm 436a Shaft 443a Shaft 443a Hole 701 Operation mode selection unit 702 Image formation start unit 703 Image formation unit 704 Output bin tray determination unit 705 Tray stack weight calculation unit 706 Stack limit weight storage unit 707 Comparison unit 708 Stack limit over setting unit 709 Image formation stop unit 710 Bin tray drive Device 711 Sheet ejection device 712 Sheet ejection sensor 713 Stacking limit alarm generating means 714 Sheet presence sensor 715 Stacking weight Reset means B (B1, Bn) Bin tray Ba Base end of bin tray Bb Sheet storage surface of bin tray BC1, BC2 Notch S401 Non-sort path sensor S402 Sort path sensor S403a Matching bar home sensor S404 Lead cam sensor S405 Bin home position S406 Manual Staple key S407 Sheet presence sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 15/00 530 G03G 15/00 530 3F343 21/00 386 21/00 386 500 500 F Term (Reference) 2C061 AQ05 AQ06 AR01 AS02 AS04 AS13 AS14 HH01 HJ04 HK06 HK23 HV01 HV09 HV13 HV14 HV32. AA04 AA05 AB01 BA02 BA04 BA07 BB02 BC03 CA03 CA05 CB03 DA01 DA09 DC05 EA03 EA12 EB06 EB09 3F050 BE11 CB02 CB05 CB06 CB08 CD07 CE06 CF01 LA02 LA05 LA07 LB03 3F343 FA02 FB02 FB03 FB04 FC06 FC01 GA01 GB01 GB01

Claims (10)

[Claims] 1. An image forming means for forming an image on a sheet, a sheet discharging means for discharging a sheet on which an image is formed by the image forming means, and a sheet placing means for stacking the sheet discharged by the sheet discharging means And determining the excess of the sheet mounting unit based on the weight information of the sheet on which the image is being formed and the accumulated weight information of the sheets already stacked on the sheet mounting unit. An image forming apparatus comprising: an excess load determining unit. 2. The storage device according to claim 1, wherein said excess load determining means stores load limit weight information as a maximum load amount of the sheet placing means and cumulative weight information of sheets already loaded on the sheet placing means. Calculating means for adding the weight information of the sheet on which an image is being formed to the cumulative weight information stored in the storing means; comparing means for comparing the calculation result of the calculating means with the load-limited weight information stored in the storing means; 2. The image forming apparatus according to claim 1, further comprising: an excess load detecting unit that detects an excess load of the sheet placing unit based on a comparison result of the comparing unit. 3. The weight information corresponding to a sheet on which an image is being formed is selected from a weight information group classified in advance according to the type or size of the sheet. 3. The image forming apparatus according to 2. 4. A stop means for stopping an image forming operation when the excess load determination means determines that the load is excessive, and a user is notified of the excess load when the excess load determination means determines that the load is excessive. 4. The image forming apparatus according to claim 1, further comprising: a stacking excess warning unit that issues a warning. 5. The apparatus according to claim 1, further comprising a plurality of sheet placement units, wherein the excess stacking determination unit determines weight information of the sheet during image formation and a sheet placement unit that is a discharge destination of the sheet among the plurality of sheet placement units. 5. The image forming apparatus according to claim 4, wherein it is determined based on the accumulated weight information that the sheet stacking means has exceeded the stacking capacity. 6. The image forming apparatus according to claim 5, further comprising a plurality of image forming modes, wherein said stopping means changes a stop timing of image forming according to the image forming mode. 7. The image forming mode includes a sort mode for collating sheets in a page order and sorting the sheets into a plurality of sheet placing units when producing a plurality of copies of an image composed of a plurality of pages. 7. The image forming apparatus according to claim 6, wherein in the case of the sorting mode, when it is determined that the stacking is excessive, the image forming operation is stopped after all the images of the page are created. 8. The image forming apparatus according to claim 4, wherein the overload warning unit warns of overload by displaying a message or lighting a lamp. 9. A sheet presence / absence sensor for detecting whether or not a sheet is loaded on the sheet loading means, wherein the excess loading determination means determines that a sheet has been removed from the sheet loading means by the sheet presence / absence sensor. 9. The apparatus according to claim 4, wherein when detected, the accumulated weight information of the sheet stacking means is reset.
Item 10. The image forming apparatus according to item 1. 10. The apparatus according to claim 9, wherein the overload warning means cancels the overload warning when the sheet presence / absence sensor detects that the sheet has been removed from the sheet loading means. Image forming apparatus.