JP2000296923A - Sheet material conveyance device, image reading device, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet material conveyance device capable of stable and efficient paper feeding. SOLUTION: A conveyance roller conveying documents and a separation roller is contacted and separated by raising the conveyance roller. When a preseparation sensor upstream of this roller pair detects a document (S112), the roller pair gradually opens from a closed state (S113), and stops when a downstream postseparation sensor detects the document (S114, S115). A count of a roller raised amount is stored as a gap opening amount and added to a gap opening total amount (S116), and when the gap opening total amount exceeds a predetermined value D1 (S117), the gap opening total amount is cleared (S118), and a document holder is raised a predetermined amount D2 (S119).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying apparatus for conveying a sheet, and is applied to, for example, an image reading apparatus for reading a sheet original and an image forming apparatus for recording an image on a sheet recording medium. The present invention relates to a sheet conveying apparatus that can be suitably implemented when a large amount of documents and recording materials are stably and efficiently fed.

[0002]

2. Description of the Related Art Conventionally, when a document stacked on a document table is continuously fed, when a document is detected by a document feed sensor based on detection information of a document feed sensor for detecting the document, When the document is fed, and when the document is not detected, the document table is raised and then fed, the timing for raising the document table is determined, and the sheet is fed.

In such a document feeder, if a document is continuously fed while the document feed sensor is detecting the document, the document table does not rise, so that the document stacked on the document table is not raised. Is lower by the thickness of the document each time one sheet is fed (FIG. 12).

As the paper feeding is continued, the uppermost position of the document is displaced to a position where the document feeding sensor is turned off, and the next feeding after the turning off is performed after the document table is raised (FIG. 13).
Further, since the resolution of the document feed sensor is lower than the thickness of the document, detection information corresponding to a displacement corresponding to the thickness of one document cannot be obtained (FIG. 14).

Therefore, the detection information of the document feed sensor is
The document table cannot be raised due to the displacement amount of the document top position.

On the other hand, a pickup roller for taking in a document on a document table has a stronger force (feeding force) as the pressure received from the document table is larger, and is weaker as the pressure is smaller.

[0007] In order to perform stable paper feeding, it is better that pressure fluctuation to the pickup roller is small. Since this pressure is affected by the uppermost position of the original, reducing the displacement of the uppermost position of the original reduces the pressure fluctuation.

[0008]

However, if the platen is raised only by the detection information of the document feed sensor as in the prior art, the platen rises after the document feed sensor is turned off.
The displacement amount of the uppermost position of the document becomes large. Therefore, stable paper feeding may not be performed. Further, since the document table rises at one time, a time loss occurs only for the time required for the rise, so that rhythmic conveyance cannot be performed and smooth paper feeding cannot be performed.

When the document table is operated only by the detection information of the document feed sensor, the amount of displacement of the uppermost position of the document becomes large, and there is a problem that the feeding is not stable and the feeding efficiency is deteriorated. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems and to provide a sheet conveying apparatus capable of stably and efficiently feeding a sheet, an image reading apparatus and an image forming apparatus having the same. With the goal.

[0011]

In order to achieve the above object, the present invention provides a sheet material loading means for loading a sheet material,
Sheet material feeding means for pressing the uppermost sheet material loaded on the sheet material loading means to take in the sheet material, and sheet material conveying means for conveying the sheet material taken in by the sheet material feeding means; Moving means for moving the sheet material stacking means to the sheet material feeding means side, and movement control means for controlling movement of the moving means, wherein the sheet material conveying means rotates in a sheet material conveying direction. In a sheet material transporting apparatus having a transport member that sandwiches a sheet material between a rotator and the transport rotator, an interval adjustment mechanism that adjusts an interval between the transport rotator and the transport member each time a sheet material is transported, Storage means for adding an index corresponding to the interval between the transport rotating body and the transport member when the transported sheet material is transported, and storing the added value, wherein the movement control means comprises: Added value of the stored index if it exceeds a predetermined value, characterized in that is moved by a predetermined amount said sheet material stacking means to said sheet feeding means side.

With this configuration, the sheet material stacking means is moved based on the index corresponding to the distance between the conveying rotating body and the conveying member, which is adjusted each time the sheet material is conveyed. Control based on the thickness of the sheet material thus performed becomes possible. Accordingly, the displacement of the position of the uppermost sheet material stacked on the sheet material stacking means can be suppressed, and the fluctuation of the contact pressure of the sheet material feeding means with respect to the uppermost sheet material can be suppressed, so that stable and efficient operation can be achieved. Sheet material can be fed.

Here, the added value of the index stored in the storage means may be deleted each time the sheet material stacking means is moved, and may be added again until the index exceeds a predetermined value.

Further, the predetermined movement amount of the sheet material stacking means may be an added value of an interval between the transport rotating body and a transport member when the sequentially transported sheet material is transported.

Since the distance between the conveying rotating body and the conveying member when conveying the sheet material is substantially equal to the thickness of the sandwiched sheet material,
The sheet stacking means moves by an amount substantially equal to the change in the position of the uppermost sheet. Therefore, regardless of the thickness of the sheet material, the sheet material stacking means can be moved so that the position of the uppermost sheet material is substantially constant,
Variations in the contact pressure of the sheet material feeding means with respect to the uppermost sheet material can be suppressed, and stable and efficient sheet material feeding can be realized.

In addition, upstream and downstream detecting means for detecting the sheet material are provided on the upstream side and the downstream side of the sheet material conveying means in the sheet material conveying direction, respectively. The sheet material detected by the upstream detection means is adjusted so that the distance gradually increases from the state where the conveyance member contacts the conveyance member, and the sheet material detected by the upstream detection means passes between the conveyance rotating body and the conveyance member, and the downstream detection means. May be stored in the storage means.

With this configuration, the interval between the conveying rotating member and the conveying member during the conveying of the sheet material is adjusted so as to be substantially equal to the thickness of the sandwiched sheet material, and the index corresponding to the interval at that time is adjusted. Is stored in the storage means, it is possible to perform control that more faithfully reflects a change in the position of the uppermost sheet material of the sheet material stacking means.

[0018] A stacked sheet material detecting means for detecting the sheet material on the sheet material stacking means may be provided.

According to this configuration, it is possible to control the movement of the sheet material stacking means based on the index corresponding to the interval of the sheet material conveying means and to control based on the detection result of the stacked sheet material detecting means. Become. Further, even when the resolution of the stacked sheet material detecting means is low, stable and efficient sheet material conveyance is possible.

Further, the transport member may be a rotatable separating member which is rotatably provided in a direction opposite to a sheet material transport direction and separates the taken-in sheet material.

In this way, double feeding of the sheet material can be prevented, so that the sheet material can be accurately conveyed.

Further, the transport rotary member and the separation rotary member may be arranged in a comb shape in a direction substantially perpendicular to the sheet material transport direction.

Also, in an image reading apparatus provided with image reading means for reading an image of a sheet-shaped document and document feeding means for feeding a document to the image reading means, the sheet feeding device according to the present invention is used as the document feeding means. A device may be provided.

According to this configuration, a sheet-shaped document can be stably and efficiently conveyed, so that it is possible to provide an image reading apparatus capable of stably and efficiently reading an image.

Further, in an image forming apparatus provided with an image forming means for forming an image on a sheet-like recording material and a recording material conveying means for conveying the recording material to the image forming means, the present invention may be applied to the recording material conveying means. May be provided.

With this configuration, the sheet-shaped recording material can be stably and efficiently conveyed, so that an image forming apparatus capable of forming a stable and efficient image can be provided.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) Hereinafter, a first embodiment of the present invention will be described. FIG. 1 is a cross-sectional view of a document feeder which is an embodiment of a sheet feeder according to the present invention, and each function will be described. The document transport device is also an image reading device provided with image reading means for reading a sheet-shaped document.

The document table 1 serving as a sheet material stacking means can be moved up and down by moving means (not shown), and can stack a large number of sheet-shaped documents.

The lower limit sensor 3 and the upper limit sensor 4 detect the document table lower limit position and the upper limit position, respectively.

The document feed sensor 5 detects the document 2 on the document table 1.
Is detected.

The pickup roller 6 serving as a sheet material feeding means rotates in the conveying direction to take in the original 2 on the document table 1 and conveys it to the comb-shaped roller A (sheet material conveying means).

Pre-separation sensor 7 as upstream detection means
Detects that the original 2 to be captured has reached just before the comb-shaped roller A.

The comb-shaped roller A separates and transports a document by rotating a feed roller (transportation rotary member) 8 in the transport direction and a separation roller (transportation member, separation rotary member) 9 in the reverse direction. . Further, the feed roller 8 can be moved up and down by an interval adjusting mechanism (not shown) so as to be able to contact and separate.

Separation sensor 10 as downstream detection means
Detects that the document 2 to be taken is passing through the comb-shaped roller A.

The pre-registration roller sensor 11 detects that the document 2 has reached just before the registration roller 12.

The registration roller 12 conveys the document 2 while rotating at a predetermined interval. The post-registration sensor 13 detects that the document 2 is passing through the registration roller 12.

Image input sensor (image reading means) 14, 1
5 acquires the image data of the document to be conveyed.

The pair of rollers 16 to 19 are rotated and driven in synchronization with a main transport motor (not shown) to transport the original 2 while pinching it.

The transport path 20 is a transport path through which the document 2 passes. The paper discharge tray 21 places the document 2 conveyed through the conveyance path 20.

The storage means 22 stores a total value obtained by adding a moving amount (gap opening amount) by which the feed roller 8 moves upward and a gap opening amount for each sheet (a total gap opening amount).
Are respectively stored. Here, the gap opening amount is an index corresponding to the distance between the conveying rotating body and the conveying member, and the total gap opening amount is an added value thereof.

Next, the operation of the first embodiment will be described with reference to the flowcharts shown in FIGS.

When the operator of the document feeder according to the present embodiment presses a feed start button (not shown) of the document feeder to start feeding, the CPU (not shown) of the document feeder sends the feed roller 8 of the comb-shaped roller A to the feed roller 8. The position of the separation roller 9 is set so as to be in contact with the comb teeth (gap home) (S10).
0), the total gap opening amount of the storage means 22 is cleared (S101). Here, the CPU is a control means of the interval adjusting mechanism of the sheet material conveying means, and is also a movement control means of a document table which is a sheet material stacking means.

Then, the CPU determines whether or not the document 2 is on the document table 1 based on the detection information of the document feed sensor 5 (S102). If not, it is determined from the detection information of the upper limit sensor 3 whether the document table 1 has reached the upper limit position (S10).
3). If the upper limit sensor 4 is also negative, the total gap opening amount is cleared, the document table is raised (S104, S105), and the process waits until one of the sensors is turned on. When raising the platen, the CPU always clears the total gap opening amount.

When the upper limit sensor 4 is turned on, the CPU determines that the document 2 is no longer on the platen 1 and lowers the platen 1 until the lower limit sensor 3 is turned on to finish the sheet feeding operation (S106 to S106). S109). Then, it waits for the operator to press the transport start button.

When the document feed sensor 5 is turned on, C
The PU stops the document table 1 (S110), and starts the operation of each roller of the pickup 6, the feed 8, and the separation 9 (S1).
11). The original 2 is taken in by the pickup roller 6 and is conveyed to the comb-shaped roller A.

The CPU grasps the position of the document 2 from the detection information of the pre-separation sensor 7 located immediately before the comb-shaped roller A, and triggers the ON of the detection information as a trigger (S112).
The feed roller 8 is raised. At this time, the gap opening amount for counting the moving amount of the feed roller 8 is cleared (S113).

As the feed roller 8 rises, the comb-shaped roller A gradually separates, and finally becomes a gap through which a document can pass. When the gap is generated, the document starts passing between the comb-shaped rollers A.

The CPU grasps the position of the document 2 from the detection information of the post-separation sensor 10 located immediately after the comb-shaped roller A,
When the detection information is turned on, the ascending of the feed roller 8 is stopped (S115), and at the same time, the gap opening amount is stored in the storage means 22 (S116, FIG. 3).

The gap opening required for the generated gap is a value corresponding to the thickness of the document. Further, when one document is fed, the uppermost position (the uppermost position of the document) of the documents stacked on the document table is displaced, and a value corresponding to the displacement amount is obtained.

Here, a description will be given of the document table predictive raising control (S116 to 119) which is a feature of the control. Each time a document is fed, this gap opening amount is added and stored in the storage unit 22 as the total gap opening amount (S11).
6). Since the CPU always clears the total gap opening amount when the platen rises, the value is always a value corresponding to the amount of displacement from the reference position with respect to the document top position after the platen rises. (FIG. 4).

By storing the total gap opening amount, the CPU can grasp the displacement amount of the uppermost position of the document and determine the timing of raising the document table.

The CPU determines whether the total gap opening amount has exceeded a predetermined value D1 (S117). If not, the CPU waits until the document completely passes from the separation sensor 10 (S12).
0). If it exceeds, clear the total gap opening (S
118), the document table is raised by a predetermined amount D2 according to a document kitchen fixed amount D2 raising routine described later (S119).

In addition to the detection information of the document detection sensor 5 by such a document table predictive raising control, the displacement of the uppermost position of the document can be reduced by raising the document table using the total gap opening amount as a trigger. (FIG. 5).

After the CPU raises the document table by a predetermined amount D2,
Wait until the document completely passes from the separation sensor 10 (S
120). After the passage, the pickup roller 6 and the feed roller 8 are stopped (S121), and the gap home is set (S122).

When the gap between the comb-shaped rollers A returns to the original position, the CPU starts an operation for feeding the next original, and repeats this operation until there is no more original on the original platen 1.
After the paper has been fed, the apparatus waits for the operator to press the transport start button.

Next, according to FIG.
The ascending routine will be described. First, D2 is set in the ascending counter (S301). Next, the document table 1 is raised by one pulse (S302), and the lift counter is decremented by one (S303). It is determined whether or not the ascending counter is 0 (S304). If the ascending counter is not 0, the document table is elevated, and when it reaches 0, the ascending is finished (S305).

(Second Embodiment) When the document table is always raised by a predetermined amount D2 as in the first embodiment, when documents of different thicknesses are fed, the gap opening amount differs for each sheet. The total gap opening amount when exceeding the predetermined value D1 is not constant.

Although the total gap opening amount is not constant, the ascending amount D2 is constant, so that the original platen position (reference position) after the original platen is elevated is different. In addition, the document table has a predetermined amount
Even after ascending, the document feed sensor 5 may remain OFF (FIG. 7).

Therefore, in the second embodiment, the document table is raised by an amount corresponding to the total gap opening amount. The operation of the second embodiment will be described with reference to the flowcharts shown in FIG. 2, FIG. 8, and FIG. Since the configuration of the document feeder is the same as that of the first embodiment, the description is omitted using the same reference numerals.

The CPU operates the same as in the first embodiment until S115. Since only the platen prediction raising control differs, this part will be described below.

The count of the amount of rise of the feed roller 8 is stored in the gap opening amount, and the gap opening amount is added to the total gap opening amount (S201). The total gap opening is a predetermined value D
1 is determined (S202), and if not, the original platen prediction ascent control routine is terminated (S205). If it exceeds, the platen is raised by an amount corresponding to the total gap opening amount according to a routine (FIG. 9) described later (S203).

The CPU determines the upward movement amount Yf of the feed roller 8.
The total gap opening amount is converted into an original plate rising amount D3 from the relationship between the original document table moving amount Yt (FIG. 10) (S401). D3 is set in the ascending counter (S402), and the platen is set to 1
It is increased by the pulse (S403), the up counter is decreased by 1 (S404), and it is determined whether or not the up counter is 0 (S403).
405), S403, S40 until the rising counter becomes 0
4 is repeated, and the process ends when the value becomes 0 (S40).
6). After the platen is raised by D3 in this way (S402 to S406), the total gap opening amount is cleared (S204), and the platen predicted raising control is ended (S20).
5).

By raising the document table by an amount based on the total gap opening amount, the reference position is not shifted, and the displacement of the uppermost position of the document can be reduced (FIG. 11).

In the present embodiment, the sheet conveying apparatus applied to the image reading apparatus has been described. However, an image forming means using a known method such as an electrophotographic method or an ink jet method is provided. It can also be applied to an image forming apparatus that conveys a recording material.

[0065]

As described above, according to the present invention, control based on the thickness of the sheet material fed from the sheet material stacking means can be performed, and the uppermost sheet material stacked on the sheet material stacking means can be controlled. Since the displacement of the position can be suppressed and the variation of the contact pressure of the sheet feeding means with respect to the uppermost sheet can be suppressed, stable and efficient sheet feeding can be performed.

Further, it is possible to provide an image reading apparatus capable of reading a sheet-shaped document stably and efficiently.

Further, it is stable against a sheet-like recording material,
It is possible to provide an image forming apparatus capable of forming images efficiently.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a document feeder according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining an operation control procedure of a document table in the document feeder according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a relationship between detection timings of a pre-separation sensor and a post-separation sensor in the document feeder according to the first embodiment of the present invention, and a gap opening amount of a feed roller.

FIG. 4 is a diagram illustrating a relationship between a total gap opening amount and a displacement amount of a document position from a reference position in the document conveyance device according to the first embodiment of the present invention.

FIG. 5 is a diagram illustrating the total gap opening amount and the displacement of the document position from the reference position when the document table is raised by using the total gap opening amount as a trigger in the document conveying apparatus according to the first embodiment of the present invention. It is a figure which shows the relationship with quantity.

FIG. 6 is a flowchart illustrating a document kitchen fixed amount D2 increasing routine according to the first embodiment of the present invention.

FIG. 7 is a diagram illustrating a relationship between a total gap opening amount and a displacement amount of a document position from a reference position when a document having a different thickness is fed in the document feeder according to the first embodiment of the present invention. FIG.

FIG. 8 is a flowchart illustrating a procedure for controlling a predicted movement of a document table in a document feeder according to a second embodiment of the present invention.

FIG. 9 is a flowchart illustrating an amount increasing routine based on the total amount of document table gap opening according to the second embodiment of the present invention.

FIG. 10 is a diagram illustrating a relationship between an upward movement amount Yf of a feed roller and a movement amount Yt of a document table in a document conveyance device according to a second embodiment of the present invention.

FIG. 11 is a diagram illustrating a document feeder according to a second embodiment of the present invention, in which a document table is raised by an amount based on the total gap opening amount and the reference position of the document position and the gap total opening amount; FIG. 5 is a diagram showing a relationship between the displacement amount and the displacement amount.

FIG. 12 is a diagram showing a change in the uppermost position of a document at the time of sheet feeding in a conventional document feeder.

FIG. 13 is a diagram showing a change in the uppermost position of a document when a document table is raised in a conventional document feeder.

FIG. 14 is a diagram showing the relationship between the resolution of a document feed sensor and the uppermost position of a document in a conventional document feeder.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 document table 2 document 7 sensor before separation 8 feed roller 9 separation roller 10 sensor after separation 14, 15 image input sensor 22 storage means A comb-shaped roller

Continued on the front page F-term (reference) 2H076 AA04 BA15 BA35 BA48 BA63 BB05 3F343 FA03 FB02 FC01 GA01 GB01 GC01 GD01 HA12 HA33 HB04 HD16 JA01 JD03 JD09 JD33 JD34 LA04 LA14 LC03 MA03 MA13 MA36 MA54

Claims (8)

[Claims] 1. A sheet material stacking means for stacking a sheet material, a sheet material feeding means for pressing the uppermost sheet material stacked on the sheet material loading means to take in the sheet material, and the sheet material feeding means. Sheet material conveying means for conveying the sheet material taken in by the feeding means, moving means for moving the sheet material stacking means to the sheet material feeding means side, and movement control means for controlling movement of the moving means. Wherein the sheet material transporting means comprises a transport rotator rotating in a sheet material transport direction and a transport member for sandwiching the sheet material between the transport rotator, wherein the transport is performed every time the sheet material is transported. An interval adjusting mechanism for adjusting the interval between the rotating body and the conveying member, and an index corresponding to the interval between the conveying rotating body and the conveying member when the sequentially conveyed sheet material is conveyed, and the added value is recorded. The movement control means moves the sheet material stacking means to the sheet material feeding means by a predetermined amount when the added value of the index stored in the storage means exceeds a predetermined value. A sheet material transport device that is moved. 2. The apparatus according to claim 1, wherein the predetermined amount of movement of the sheet material stacking means is an addition value of an interval between the transport rotating body and a transport member when the sequentially transported sheet material is transported. A sheet material conveying device as described in the above. 3. An upstream detecting means and a downstream detecting means for detecting a sheet material on an upstream side and a downstream side of the sheet conveying means in the sheet conveying direction, respectively, wherein the interval adjusting mechanism includes The sheet material detected by the upstream-side detection means is adjusted so that the distance gradually increases from a state in which the conveyance member is in contact with the conveyance member. 3. The sheet material transporting device according to claim 1, wherein the index when the detection is performed is stored in the storage unit. 4. 4. The sheet material transporting device according to claim 1, further comprising a stacked sheet material detecting means for detecting a sheet material on said sheet material stacking means. 5. The separation member according to claim 1, wherein the conveyance member is rotatable in a direction opposite to a sheet material conveyance direction, and is a separation rotating body that separates the taken-in sheet material. The sheet material conveying device according to item 1. 6. The sheet conveying apparatus according to claim 5, wherein the conveying rotating body and the separating rotating body are arranged in a comb shape in a direction substantially orthogonal to the sheet conveying direction. 7. An image reading apparatus comprising: an image reading means for reading an image of a sheet-shaped document; and a document conveying means for conveying a document to the image reading means. An image reading device comprising the sheet material conveying device according to any one of the above. 8. An image forming apparatus comprising: an image forming unit that forms an image on a sheet-like recording material; and a recording material conveying unit that conveys the recording material to the image forming unit. An image forming apparatus comprising the sheet material conveying device according to any one of 1 to 6.