JPH058900A - Image forming device having sheet thickness detecting device - Google Patents

Abstract

PURPOSE:To perform optimum system control based on the thicknesses of a conveying document and sheet for duplication. CONSTITUTION:A drive roller 12 and a driven roller 13 positioned facing the drive roller and elevated according to the thickness of a conveying document M or sheet P are located in a conveyance route for the document M or the sheet P. A magnet MG is attached to the side of the driven roller 13 and a hall element is located in the vicinity of the driven roller 13. Thickness is detected by means of amplitude of a generating voltage VH of the hall element 15 and a conveying speed is detected based on a frequency according to the change or magnetic flux density H emanating from a magnet MG.

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 such as a copying machine, and more specifically, a sheet thickness detecting device is provided in the image forming apparatus, and the image forming system is brought into a predetermined state by a detected sheet thickness signal. The present invention relates to an image forming apparatus that switches to.

[0002]

2. Description of the Related Art A conventional image forming apparatus has a sheet thickness detecting device for detecting the thickness of an original or a sheet to be copied on a conveying path, and a sheet in an image forming system is output by an output signal thereof. Nothing is known that switches the carrying state to a predetermined state.

[0003]

However, for example, the basis weight of a document that can be used in the document feeder is generally in the range of 50 to 100 grams per square meter. If you mistakenly use an original with a low basis weight, the original will be too stiff to cause the original to buckle, causing a paper jam (jam). , The stiffness was too strong, and the loop for removing the skew of the document was not created well, and the skew occurred or the jam occurred. Even if the basis weight of the original document is within the above range, for example, for an original document having a basic weight of 50 grams per square meter and an original document having a basis weight of 110 grams,
Due to the mechanical structure, it is better to change the control as follows.
Often convenient.

Loop creation control for removing skew of a document.

Separation speed control and conveyance speed control when separating and feeding the sheets one by one.

When there are a plurality of feeding or discharging paths, the optimum path is selected and controlled according to the basis weight.

When the basis weight of the copy sheet used in the main body of the image forming apparatus is determined, in addition to the above control, the fixing property after image formation is controlled according to the basis weight.

It is considered that That is, since a sheet having an extremely large basis weight has a large amount of heat taken for fixing, it is conceivable to raise the temperature for fixing or slow the sheet conveying speed. Similarly, in a sheet post-processing apparatus such as a sorter, a bookbinding apparatus (finisher), and a punching machine that perform processing after being discharged from the image forming apparatus, as a preferable control method according to the basis weight, as shown below, It is possible to

In the sorter, the discharging speed into the sorter bin is controlled according to the basis weight and size of the sheet to improve the stackability.

With respect to the stapler or the punching machine, the maximum number of sheets and the like are monitored and controlled according to the basis weight of the sheet.

If the above is not done, an unexpected trouble may occur.

Therefore, according to the present invention, a sheet thickness detecting device is provided in an image forming apparatus, and the sheet conveying speed of a predetermined device is controlled to a predetermined state by a detection signal from the image forming device so as to adjust the sheet conveying speed. An object of the present invention is to provide an image forming apparatus having a sheet thickness detecting device that stops and adjusts the device to a predetermined state.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances. For example, referring to FIGS. 1 to 4, the document feeder (300) or sheet post-processing is shown. In the image forming apparatus (100) including the unit (1), the thickness of the original document (M) or the sheet (P) and the thickness of the original document (M) or the sheet (P) are set in the transport paths (22, 23) for transporting the original document (M) or the sheet (P). A sheet thickness detecting device (11) for detecting a conveying speed is provided, and upon receipt of a detection signal from the sheet thickness detecting device (11), the document feeding section (300), the sheet post-processing section (1) or the image forming apparatus. An instruction signal is transmitted to the main body (100) so that the original (M) or the sheet (P) is conveyed in the original feeding section (300), the sheet post-processing section (1), or the image forming apparatus main body (100). Control unit (17) for switching to a predetermined state Characterized by comprising providing.

[0014]

Based on the above construction, in the conveying path (22, 23) of the original (M) or the sheet (P), the thickness and the conveying speed of the original (M) or the sheet (P) are detected by the sheet thickness detecting device (11). ), And sends the detection signal to the control unit (17), the control unit (17) judges the situation, and the document feeding unit (300), the sheet post-processing unit (1), or the image forming apparatus. By sending an instruction signal to the main body (100), the document feeding section (300), the sheet post-processing section (1), or the main body (10).
The conveyance state of the document (M) or the sheet (P) in 0) is switched to a predetermined state.

The reference numerals in the parentheses refer to the drawings and do not limit the structure of the present invention.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 4 shows an example of an image forming apparatus equipped with the sheet thickness detecting device of the present invention.

In the image forming apparatus main body 100, 101
Is a platen glass on which the original is placed, 103 is an illumination lamp (exposure lamp) for illuminating the original, 105, 107, 1
Reference numeral 09 is a scanning mirror for changing the optical path of the original, 11
Reference numeral 1 is a lens having a focusing and zooming function, 113 is a reflection mirror (scanning mirror) that changes the optical path, 115 is an optical system motor that drives an optical system, and 117 and 121 are sensors, respectively.

Reference numeral 131 is a photosensitive drum, 133 is a main motor for driving the photosensitive drum 131, 135 is a high voltage unit, 137 is a blank exposure unit, 139 is a developing device,
140 is a developing roller, 141 is a transfer charger, 143 is a separation charger, and 145 is a cleaning device.

Reference numeral 151 is an upper cassette, 153 is a lower cassette, 171 is a manual paper feed port, 155 and 157 are paper feed rollers, and 159 is a registration roller. Also, 161
Is a conveyor belt that conveys the image-recorded sheet P to the fixing side, 163 is a fixing device that fixes the conveyed sheet by thermocompression bonding, 165 is a roller that sends the fixed sheet P to a pedestal to be described later, and 167 is both sides This is a sensor used for sheet detection during multiple recording.

The surface of the above-mentioned photosensitive drum 131 is composed of a photoconductor and a seamless photosensitive member using a conductor, and the photosensitive drum 131 is rotatably rotatably supported and responds to depression of a copy start key. The operation of the main motor 133 starts rotation in the direction of the arrow. Then, drum 13
When the predetermined rotation control processing and the potential control processing (preprocessing) of No. 1 are completed, the document M placed on the platen glass 101 is illuminated by the illumination lamp 10 that is configured integrally with the first scanning mirror 105.
And the reflected light from the original M is illuminated by the mirror 10.
5, the mirror 107, the mirror 109, the lens 111, and the mirror 113, and the image is formed on the drum 131.

The drum 131 is corona-charged by the high-voltage unit 135, and then the image (original image) irradiated by the illumination lamp 103 is slit-exposed to form an electrostatic image on the drum 131 by the known Carlson method.

Next, the electrostatic image on the photosensitive drum 131 is developed by the developing roller 140 of the developing device 139 and visualized as a toner image, and the toner image is transferred to the transfer charger 141.
Is transferred onto the sheet P as described below.

On the other hand, the sheet P in the upper cassette 151 or the lower cassette 153 or the sheet P manually inserted in the manual paper feed port 171 is fed by the paper feed rollers 155, 157.
Alternatively, the sheet is fed into the main body apparatus by 154 and further fed by the registration roller 159 toward the photosensitive drum 131 with accurate timing, and the leading edge of the latent image and the leading edge of the sheet P are aligned. After that, the transfer charger 141 and the drum 1
As the sheet P passes between the drum 1 and the drum 31,
The toner image on 31 is transferred onto the sheet P. After the transfer is completed, the sheet P is separated from the drum 131 by the separating charger 143.
Separated by the fixing belt 163 and fixed by the conveying belt 161.
Then, after being fixed by pressing and heating, the sheet is discharged to the outside of the main body 100 by the discharging roller 165.

After the transfer, the drum 131 continues to rotate and its surface is cleaned by the cleaning device 145 including a cleaning roller and an elastic blade.

Reference numeral 200 is a pedestal that temporarily receives the sheet P sent from the copying machine main body 100 and holds it for post-processing. The pedestal 200 is the main body 100.
The intermediate tray 2 for double-sided copying and the deck 201 that can be separated from the sheet P and can store about 2000 sheets P
And 03. Further, the lifter 205 of the deck 201 capable of accommodating about 2000 sheets ascends according to the amount of the sheet P so that the sheet P always contacts the sheet feeding roller 207.

Reference numeral 211 denotes a flapper for switching between a double-sided recording side or multiple recording side path and a discharge side path.
Denoted by 3 and 215 are conveyance belt conveyance paths, and 217 is a sheet pressing intermediate tray weight, and the transfer paper that has passed through the discharge flapper 211 and the conveyance paths 213 and 215 is turned over and stored in the double-sided copying intermediate tray 203. To be done. Reference numeral 219 denotes a multiple flapper that switches between double-sided recording and multiplex recording paths. The multiple flapper 219 is disposed between the transport paths 213 and 215 and can rotate the sheet upward to guide the sheet P to the multiple recording transport path 211. .. Reference numeral 223 denotes a multiple paper discharge sensor that detects the end of the sheet P when the multiple flapper 219 is driven. Reference numeral 225 is a paper feed roller that re-feeds the sheet P to the drum 131 side through the path 227, and 229 is a discharge roller that discharges the sheet P outside the machine.

At the time of double-sided recording (double-sided copying) or multiplex recording (multiplexing copying), first, a paper discharge flapper 211 of the main body 100.
Is rotated upward to store the copied sheet P in the intermediate tray 203 via the conveyance path 213 or 215 of the page distal 200. At this time, the multiple flapper 219 is lowered in the case of double-sided recording, and the multiple flapper is raised in the case of multiple recording. This intermediate tray 203
Can store, for example, up to 99 sheets P, and the sheets P stored in the intermediate tray 203 are pressed by the intermediate tray weight 217. Then, at the time of the back side recording or the multiplex recording to be performed next, the intermediate tray 20
The sheets P stored in No. 3 are routed one by one from the bottom by the action of the sheet feeding roller 225 and the weight 217.
Through the registration roller 159 of the main body 100.

Reference numeral 300 denotes a circulation type document feeding device (hereinafter referred to as RDF) which sequentially feeds the documents M in a circulation type.
In F300, 305 is a stacking tray on which a stack of documents M is set. In the stacking tray, a separation motor (not shown) is driven at the time of a single-sided original so that the half-moon roller 307, the separation / conveyance roller 309, and the separation belt 3 are driven.
10 allows the originals M to be fed one by one from the bottom of the bundle of originals M.
Is separated, and the belt motor 302 is driven, so that the registration roller 312 and the entire surface belt 303 convey the sheet to the exposure position on the platen glass 101, and then stop, and the copying operation starts. And after copying,
When the motor 302 is driven again, it is guided to the path V by the large conveyance roller 315, and further, the paper discharge roller 3
By means of 17, it is returned to the upper surface of the bundle of originals M again. 306
Is a recycle lever that detects one circulation of the original document, and is kept in a state of being placed on the upper part of the bundle of the original documents M at the start of feeding the original documents. When the recycle lever 306 is removed, the circulation of the original document is detected by dropping the recycle lever 306 under its own weight.

Reference numeral 1 denotes a post-processing device (a sorter, a bookbinding machine, a punching machine, etc. are connected) for the sheet P discharged from the image forming apparatus.

Next, in the RDF 300, the sheet thickness detecting device 11 for the fed original M is shown in FIG. 2, and the sheet thickness for the sheets P fed from the cassettes 151 and 153 and the deck 201 or the sheet P manually fed. The detection device 11 is shown in FIG. In FIG. 2, it is provided on the transport path 22 on the upstream side of the registration roller 312, and on the transport path 23 on the upstream side of the registration roller 159 in FIG. A driving roller 12 which is rotatably fixed and whose axial center position is fixed is provided on the conveying path, and the driving roller 12 faces the driving roller 12 and has a thickness of the original M or the sheet P to be conveyed. A driven roller 13 that moves up and down accordingly is provided. And this driven roller 1
A magnet MG is attached to the side of the Hall element 3, and the Hall element 15 is provided near the driven roller 13 (upward in the figure).
Is provided. The Hall element 15 is the amplifier 1
6, the signal line from the control circuit 17 is connected to the document feeding apparatus 300, the main body 100 of the image forming apparatus, and the predetermined devices of the sheet post-processing apparatus 1. ..

Next, the operation of the sheet thickness detecting device 11 will be described with reference to FIGS. 1, 5 and 6.

When the document M or the sheet P is fed and passes through the sheet thickness detecting device 11, the driven roller 13 moves upward (in the direction of arrow X) in accordance with the thickness of the document M or the sheet P. , And rotates according to the conveyance speed of the document M or the sheet P. As a result, in the magnetic flux density H of the magnet MG, the generated voltage VH of the hall element 15 increases as the magnet MG approaches the hall element 15. FIG. 5 shows a state where the rotation speeds of the rollers 13 are the same. As the roller 13 rotates, the magnet M
The rotation of G causes the voltage VH generated in the hall element 15 to increase or decrease, and when this is shown on the horizontal axis, the waveform shown in FIG. 5 is obtained. The thicker the document M or the sheet P, the closer the magnet MG is to the Hall element 15, and the higher the peak of the waveform. The dotted line shows the waveform for the thin document M or sheet P.

Further, as shown in FIG. 6, when the conveying speed of the original M or the sheet P is fast, the pitch of the waveform is short, and when it is slow, the pitch of the waveform is long.
Alternatively, the conveyance speed of the sheet P can be detected. The control circuit 17 receives a signal obtained by amplifying the voltage VH generated by the original roller M or the sheet P rotating the magnet MG by the driven roller 13 by the amplifier 16, and the height of the voltage signal and the frequency of the waveform. The judgment is made based on the result of obtaining the information of the thickness of the original M or the sheet P and the conveying speed, and the signal is transmitted to the RDF 300, the image forming apparatus main body 1
00, the sheet post-processing apparatus 1 is controlled to perform the following control.

Loop creation control for removing skew of the original M or the sheet P This is for abutting the original M or the sheet P against the registration roller 312 or 159.
Is installed immediately after the separating / feeding device, and the registration roller 3
A certain distance must be held by 12 or 159. Then, when the information on the transport speed and the thickness of the original M or the sheet P is obtained, the control circuit 17 causes the feed rollers 154, 155, 157 to have the stored transport speed and the abutting amount under the optimum conditions. , 207 and 309 are adjusted. Generally, for thick paper, slow the transport speed to reduce the transport amount (loop amount), and for thin paper, similarly slow the transport speed to transport amount (loop amount).
Is something that

Control of Separation Speed and Conveyance Speed when Separately Feeding Sheets One By One Since the sheet thickness detecting device 11 is provided downstream of the separating / feeding device, for the first original M or sheet P. Can be controlled from the middle and is effective for the second document M or sheet P in the same group. Also, the first sheet P
Is also effective when re-feeding. Since the friction and the load change depending on the thickness of the sheet P or the document M,
The control circuit 17 receiving the thickness signal causes the document feeding device 30
At 0, the half-moon roller 307 and the separation / conveyance roller 309.
The image forming apparatus main body 100 with respect to the separation belt 310.
In step 1, the sheet feed rollers 155, 157 or 154 are instructed, and in the deck 201, the sheet feed roller 207 is instructed to reduce the separation / conveyance speed.

When there are a plurality of conveyance paths for feeding or discharging, the optimum conveyance path is selected according to the thickness of the original or sheet. When a thick original M or sheet P is mistakenly fed. ,
The relationship between the degree of bending of the conveying path and the conveying speed corresponding to the degree of bending is stored in the control circuit 17, and when the document M or the sheet P that does not conform to the conveying path is conveyed, the conveying speed is changed. The conveyance speed is adjusted for those that can be conveyed by the adjustment of No. 2, and the conveyance is stopped immediately for the original M or the sheet P having an impossible thickness, and if possible, a display to that effect is displayed. The jam handling is facilitated by stopping the transportation in the initial stage.

Control of Fixability after Image Formation According to Basis Weight If the sheet P is thick, the control circuit 1 shows the relationship between the appropriate thickness of the sheet P and the transport speed depending on the heat generation capacity of the fixing device 163.
7, the control circuit 17 receives the signal from the sheet thickness detecting device 11 and adjusts the conveyance speed of the sheet P. Alternatively, if the heat generation capacity of the fixing device 163 can be increased for the sheet P whose conveyance speed is faster than the thickness, the heat generation amount of the fixing device is adjusted so as to correspond to the conveyance speed and the sheet thickness. The control circuit 17 increases the fixing device 1 so as to increase.
Instruct 63.

In the sorter, the discharging speed to the bin of the sorter is controlled according to the basis weight and the size of the sheet to improve the stackability. The control circuit 17 which receives the detection signal of the thickness of the sheet P and the conveying speed thereof The size data is also determined and a signal is sent to the post-processing apparatus 1 to increase the discharge speed of the sheet material P when the sheet material P is thick so as to improve the stackability.

The maximum number of sheets to be processed is controlled by the stapler or puncher of the post-processing apparatus according to the basis weight of the sheet. When the sheet detecting device 11 detects the thickness of the sheet P, the control circuit 11 receives the signal, and limits the maximum number of sheets to be processed by the stapler or the puncher.

Next, another embodiment will be described with reference to FIGS.

In this embodiment, a magnetoresistive element 19 is provided instead of the Hall element 15 in the embodiment shown in FIG. The resistance value RH of the magnetoresistive element 19 increases or decreases as the magnetic flux density H increases or decreases. Therefore, this resistance value R
The H is amplified by the amplifier 16 and transmitted to the control circuit 17.

Incidentally, FIG. 8A corresponds to FIG. 5 of the above embodiment, and FIG. 8B corresponds to FIG.

The operation and effect of this embodiment are similar to those of the previous embodiment.

Next, still another embodiment will be described with reference to FIGS.

In this embodiment, the driven roller 1 shown in FIG.
3 is a magnetized roller body 20 having an uneven surface and alternating N and S poles.
A coil 21 in which a conductive wire is wound around an iron core is provided in the vicinity of.

As the roller body 20 rotates, the direction of the magnetic flux H in the coil 21 changes every time it corresponds to the convex portion, so that the voltage VH is induced in the coil. This voltage VH has an AC waveform as shown in FIG. Since the magnetic flux H becomes stronger as the sheet thickness becomes thicker, the amplitude thereof becomes larger and the frequency becomes larger as the rotation becomes faster. Therefore, the action and effect of this embodiment are the same as those of the embodiment shown in FIG. Is the same.

[0048]

As described above, according to the present invention,
When the sheet thickness detecting device detects the thickness of the original or the sheet and the conveying speed in the conveying path and sends the detection signal to the control section, the control section judges the situation, and the original feeding section and the sheet post-processing are performed. Since the unit or the main body of the image forming apparatus is switched to a predetermined state, optimum system control can be performed in the image forming apparatus.

[Brief description of drawings]

FIG. 1 is a block diagram showing a sheet thickness detection device according to an embodiment of the present invention.

FIG. 2 is a side view showing a state in which a sheet thickness detecting device is applied to the document feeding device.

FIG. 3 is a side view showing a state in which a sheet thickness detecting device is applied to the image forming apparatus main body.

FIG. 4 is a sectional side view of an image forming apparatus to which the present invention is applied.

FIG. 5 is a diagram showing a detection signal generated by the sheet thickness detecting device of the present invention corresponding to the sheet thickness.

FIG. 6 is a diagram showing a frequency difference of detection signals generated corresponding to the sheet thickness.

FIG. 7 is a block diagram of a sheet thickness detecting device according to another embodiment.

8A is a diagram showing a detection signal emitted corresponding to the sheet thickness, and FIG. 8B is a diagram showing a frequency difference emitted corresponding to the sheet thickness.

FIG. 9A is a block diagram of a sheet thickness detecting device according to still another embodiment, and FIG. 9B is a side view showing a relationship between a multi-pole magnetized roller body and a coil.

FIG. 10 is a diagram showing a waveform of the detection signal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sheet post-processing section (post-processing apparatus) 11 Sheet thickness detection apparatus 17 Control section (control circuit) 22, 23 Conveying path 100 Image forming apparatus main body 300 Original feeding section (original feeding apparatus) M Original P sheet

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location G03G 15/20 109 6830-2H

Claims (1)

Claim: What is claimed is: 1. An image forming apparatus comprising an original feeding section or a sheet post-processing section, wherein a thickness and a conveyance speed of the original or the sheet are detected in a conveyance path for conveying the original or the sheet. A sheet thickness detecting device for receiving the detection signal of the sheet thickness detecting device, and transmitting an instruction signal to the document feeding unit, the sheet post-processing unit, or the image forming apparatus main body, An image forming apparatus having a sheet thickness detecting device, which is provided with a control unit for switching a conveying state of the document or the sheet in the processing unit or the main body of the image forming apparatus to a predetermined state.