JP2001002272A - Paper carrying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely detect the small difference of the paper thickness and the mixture of fine foreign matters between paper carrying members by providing pressure sensitive bodies for detecting the pressure for holding the paper to be carried, on a paper carrying member, and controlling the paper carrying on the basis of the detected pressure by the pressure sensitive bodies. SOLUTION: A plurality of pressure sensitive bodies 22a made of pressure sensitive rubber and electrically insulated from an adjacent pressure sensitive body 22a, are wound in the axial direction of a crust roller 22 of a carrying roller with pressure sensitive bodies. Detecting elements 21a are mounted on parts opposite contacting with pressure sensitive bodies 22a of the crust roller 22 for detecting a resistance value of the pressure sensitive bodies 22a through a cable 4, and connected to a determining part 25 for detecting the pressure applied to the pressure sensitive bodies 22a. When the paper is held and carried by the paper feeding roller, the load pressure for the paper thickness is applied to the roller with pressure sensitive bodies, and the load pressure is detected by the determining part 25 from the change of the resistance of the pressure sensitive bodies 22a. When the detected pressure deviates from a predetermined value by the multifeeding of the paper and the like, the rotation of the paper carrying roller is stopped.

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, a printer and a facsimile, and an image reading apparatus, which is provided with a pair of sheet conveying members for sandwiching and conveying sheets (recording paper and originals). It concerns the device.

[0002]

2. Description of the Related Art An image forming apparatus and an image reading apparatus having a conventional paper transporting apparatus are not equipped with a method for determining an abnormality such as mixing of foreign matters or double feeding. Abnormal transport was stopped, but in this case,
The abnormality detection is slow and the possibility of damaging the transport mechanism and the transport paper itself is extremely high, and the recovery from the abnormality is complicated and difficult.

In order to solve such a problem, there is a conventional technique for detecting an abnormality as disclosed in Japanese Patent Application Laid-Open No. 62-70145. That is, one of a pair of paper transport rollers for nipping and transporting the paper is disposed so as to be movable in a direction orthogonal to the paper transport direction, and the one of the paper transport rollers transports the paper. A pressure sensor is provided on the opposite side of the nipping side so that the paper transport roller abuts, and when the paper is nipped between the paper transport rollers during paper transport, one of the paper transport rollers moves according to the thickness of the paper However, the pressure applied to the pressure sensor by this movement is detected by the pressure sensor, and the passage of the sheet is detected by the detected pressure.

[0004]

However, since the pressure-sensitive sensor having the above-described structure detects a pressure change corresponding to the amount of movement when one of the paper transport rollers moves, the pressure is detected as follows.
A minute amount of movement of the sheet conveyance roller due to a minute difference in the thickness of the sheet cannot be detected, and a sheet conveyance abnormality cannot be accurately detected.

Further, the paper transport roller has elasticity, and when the difference in the thickness of the sandwiched material between the paper transport rollers during paper transport is minute, the elasticity absorbs the difference in thickness. In some cases, it may not be possible to move the paper transport roller to the pressure-sensitive sensor side. In such a case, the pressure-sensitive sensor cannot detect a pressure change.

The present invention controls the conveyance of a sheet based on the pressure detected by a pressure-sensitive member provided on a sheet conveyance member that conveys the sheet while nipping and conveying the sheet. It is an object of the present invention to make it possible to reliably detect the entry of foreign matter between sheet transport members.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a sheet conveying apparatus having a pair of sheet conveying members for pinching and conveying a sheet, wherein the sheet conveying member detects a pressure when the sheet to be conveyed is pinched. And a control means for controlling the conveyance of the sheet based on the pressure detected by the pressure-sensitive body.

A plurality of pressure-sensitive members of the present invention are provided in the width direction of the sheet.

The control means of the present invention stops the sheet conveyance when the pressure information value based on the pressure detected by the pressure-sensitive element is out of a predetermined range.

[0010] The control means of the present invention controls the paper transport speed of the paper transport member based on the pressure detected by the pressure-sensitive body.

The control means of the present invention compares the detected pressure at the time of sheet conveyance by the pressure-sensitive body with a pressure range set in advance based on the usable sheet type to thereby determine the sheet type, abnormal conveyance, and foreign matter. The presence / absence is determined and the conveyance of the sheet is controlled.

The control means of the present invention calculates an average value of the detected pressures of the plurality of pressure-sensitive bodies at predetermined time intervals, and calculates a degree of variation in the pressure in the sheet from the average value. Stop paper transport when out of range.

According to the present invention, there is provided a pressure-sensitive paper feed roller comprising a roller portion and a roller shaft for pressing and contacting a sheet feed member to pinch and feed a sheet, wherein the roller portion detects the pressure at the time of pinching and feeding the sheet. Body is provided.

The pressure-sensitive body of the present invention is made of pressure-sensitive rubber, and a plurality of such pressure-sensitive rubbers are provided so as to be electrically insulated from each other in the axial direction.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment 1 of an image forming apparatus using a sheet conveying device of the present invention will be described with reference to FIG.

This image forming apparatus, as shown in FIG.
A paper feed tray 1 containing paper, a pickup roller 2 for picking up paper one by one from the paper feed tray 1,
A pair of paper transport rollers 3 for nipping and transporting the paper picked up by the pickup roller 2, a paper transport path 4, and a pair of paper feed rollers for feeding the paper transported through the paper transport path 4 to the printing unit. 5, a print head 6 provided in the printing unit for printing on paper fed by the paper feed roller 5, and a pair of paper discharge rollers 7 for discharging the paper printed on the print head 6; It consists of.

The paper transport roller 3 comprises a pressure-sensitive transport roller 3a provided with a pressure-sensitive body on a surface which comes into contact with the paper when the paper is nipped and transported, and a normal transport roller 3b. I have.

Next, a second embodiment of an image reading apparatus using the paper conveying apparatus of the present invention will be described with reference to FIG.

A document tray 11 containing a document, a pickup roller 12 for picking up documents one by one from the document tray 11, a pair of document conveying rollers 13 for sandwiching and conveying the document picked up by the pickup roller 12, and a document. Image reading section (CIS
Or, a CCD (CCD) 14 and a back roller 15 that abuts and transports the document conveyed from the document conveying roller 13 to the image reading unit 14.

The original transport roller 13 is composed of a transport roller 13a with a pressure-sensitive body provided with a pressure-sensitive body on a surface that comes into contact with the original when the original is nipped and transported, and a normal transport roller 13b. I have.

The transport roller 3a with a pressure-sensitive element of the paper transport roller 3 of the image forming apparatus shown in the first embodiment and the transport roller 13a with a pressure-sensitive element of the document transport roller 13 of the image reading apparatus shown in the second embodiment. Since they have the same configuration, the detailed configuration of the sheet transport roller 3 of the image forming apparatus according to the first embodiment will be described with reference to FIGS.

As shown in FIGS. 3 and 4, the conveying roller 3a with a pressure-sensitive element comprises a fixed roller shaft 21, an outer roller 22 rotatably provided outside the roller shaft 21, and
A rotation gear 23 for transmitting the rotation force of the drive motor provided on the outer shell roller 22 is provided.

The outer shell roller 22 is provided by winding a plurality of pressure-sensitive members 22a made of pressure-sensitive rubber in the axial direction. The pressure-sensitive members 22a electrically connect adjacent pressure-sensitive members 22a to each other. It is provided to be electrically insulated.

The above-mentioned pressure-sensitive rubber is, for example, an element whose resistance value changes according to applied pressure, covered with rubber. In addition, a piezoelectric film, which is a piezoelectric element that generates a voltage when a pressure is applied, may be used instead of a device in which a resistance value changes due to such pressure.

Further, instead of the pressure-sensitive rubber, a silicone rubber generally used for a sheet conveying roller may be used, and the detection element may be constituted by a pressure-sensitive rubber.

The outer roller 2 of the roller shaft 21
A control element for detecting a resistance value of the pressure-sensitive body 22a by a cable 24 and detecting a pressure applied to the pressure-sensitive body 22a; Is connected to the determination unit 25.

The operation of detecting the pressure when the sheet is conveyed by the above configuration will be described with reference to FIG. The load pressure applied to the pressure-sensitive transport roller 3a of the paper transport roller 3 is
When the paper is nipped and conveyed, the load pressure corresponding to the thickness of the paper is applied, and the load pressure changes the resistance value of the pressure-sensitive body 22a of the pressure-sensitive body-conveying roller 3a. Detect pressure.

When the sheet is nipped and conveyed without any trouble during the nipping and conveying of the sheet, the pressure value applied to each pressure-sensitive member 22a becomes uniform at a value preset based on the sheet to be used.

However, when a pressure value is detected that clearly deviates from the preset value (outside the preset pressure range based on the usable paper), a double feed of the paper, There is a possibility that troubles may occur due to the mixture of foreign matter such as staples, and if the paper is transported as it is, there is a risk that the paper or the device may be damaged, and moreover, the time for solving the trouble may be lengthened. By directly detecting a change in pressure with the pressure-sensitive body-equipped transport roller 3a and stopping the rotation of the paper transport roller 3 immediately when the value is other than a preset value, it is possible to prevent damage to the paper and the apparatus. It is possible to reduce the time for solving the trouble.

Next, for example, a description will be given of a case in which the paper is transported left-justified with reference to FIG. 6. First, the pressure value of the pressure detection by the pressure-sensitive body 22a in the entire area is determined for all paper sizes, and the maximum transportable range is determined. If the pressure does not exceed the value, the presence or absence of a sheet in each pressure-sensitive body 22a is determined based on the pressure value, and the determination of the sheet size or the sheet size error (the sheet size is too large or too small) is performed. If it is determined that there is no error in the paper size, the detection value of the pressure-sensitive body 22a at the position where no paper exists (the same value as that before conveyance of the paper or the detection value of the pressure-sensitive body 22a below) is ignored, and the paper 6A, the abnormality is determined using the detection values of the eleven pressure-sensitive members 22a from the left side of the twelve pressure-sensitive members 22a in FIG. Size The detection of double feeding based on the detected pressure values of the 11 pressure-sensitive bodies 22a, and staples when the detected pressure values of some of the 11 pressure-sensitive bodies 22a are equal to or greater than a preset value. Detects abnormalities due to mixing of

In the case where the paper size is small, FIG.
As shown in (b), by determining the abnormality using the detection values of the four pressure-sensitive members 22a from the left side of the twelve pressure-sensitive members 22a, the paper size is determined. Pressure body 2
Detection of double feed by the detected pressure value of 2a, four pressure-sensitive members 22
If the detected pressure value of some of the pressure-sensitive members 22a is equal to or greater than a preset value, an abnormality is detected due to mixing of staples or the like.

Next, the operation of detecting the pressure value will be described with reference to the flowchart of FIG.

First, a sheet is picked up by a pick-up roller, and sheet conveyance is started (S1). At the same time, pressure detection by the paper transport roller is started (S
2). It is determined whether or not pressure is detected by the pressure-sensitive body of the conveyance roller with the pressure-sensitive body of the paper conveyance roller (S3), and the detected pressure value is compared with a preset allowable range. It is determined whether or not there is (S4).

If the detected pressure value is less than the allowable range, the detection pressure value is continuously determined until a predetermined time has elapsed because of the determination load, and when the predetermined time has elapsed (S5), the determination is disabled and the operation is stopped. (S6).

If the detected pressure value exceeds the allowable range, it is determined that a trouble such as staples or the like has entered during multi-feeding or conveying of the paper, the operation is stopped, and the trouble is eliminated.

When the detected pressure value is within a permissible range within a predetermined time, the paper size is determined based on the detected pressure value of each pressure sensitive element 22a. The paper size is determined, the maximum value, the minimum value, and the average value of the pressure values (calculated using the number of pressure-sensitive bodies 22a according to the paper size as a parameter) are calculated (S7), and the pressure value in the paper surface is calculated. The variation is calculated (S8).

It is determined whether or not the variation is within the allowable range. If the variation is out of the allowable range, it is determined that a trouble due to foreign matter such as staples enters during the conveyance of the sheet. Do.

If it is within the allowable range, the paper transport is continued (S9), and the steps from S8 are continued until the paper transport is completed, and the paper transport is completed (S9).
10), the sheet size and the pressure value detected by the above operation are reset (S11), and preparation and standby for the next sheet conveyance are performed (S12).

As described above, when the sheet is conveyed by the sheet conveying roller, an abnormality due to the sheet size, double feeding of the sheet, mixing of foreign matter, or the like is detected. Therefore, it is possible to determine the occurrence of the abnormality at an early stage and stop the sheet conveying. Thus, it is possible to reduce the time required to resolve troubles (abnormalities) and to minimize damage to paper and the apparatus due to abnormal transport.

Further, since the pressure change during the sheet conveyance can be directly detected by the sheet conveyance roller, a minute pressure change during the sheet conveyance can be reliably detected, and the abnormality can be accurately determined. Can be.

In the above-described embodiment, the paper transport device for the image forming unit of the image forming apparatus and the paper transport device of the document reading device have been described. However, the paper transport device of the present invention is used for the fixing device in the image forming device. The case will be described.

The fixing device includes a heating roller having a heating element and a pressure roller pressed against the heating roller, and the paper on which the toner image has been transferred is carried in between the heating roller and the pressure roller. Then, a pressure roller is formed in the same configuration as the transport roller with the pressure-sensitive element described in the first and second embodiments, and the pressure value at the time of transporting the paper by the pressure roller is used. Is detected, the type of paper (thickness, for example, the type of paper such as OPC sheets and recording paper) is determined based on the pressure value, and the conveyance speed is controlled in accordance with the type of paper. Performs good fixing of toner images.

Further, by applying the paper transport device of the present invention to a paper discharge roller and controlling the paper discharge speed based on the paper size, the total time required for image formation can be reduced.

[0044]

According to the present invention, there is provided a sheet conveying apparatus having a pair of sheet conveying members for pinching and conveying a sheet, wherein the sheet conveying member is provided with a pressure-sensitive body for detecting a pressure when the sheet to be conveyed is pinched, Since the control means for controlling the conveyance of the sheet based on the detection pressure of the pressure-sensitive body is provided, it is possible to directly detect a pressure change at the time of sheet conveyance by the pressure-sensitive body of the sheet conveyance member,
Even small pressure changes can be accurately detected.

Since a plurality of pressure-sensitive members of the present invention are provided in the width direction of the paper, the paper size can be detected, and the control based on the paper size can be performed accurately.

The control means of the present invention stops the conveyance of the sheet when the pressure information value based on the pressure detected by the pressure-sensitive element is out of the predetermined range. In some cases, the apparatus can be stopped early, so that the time required to resolve the abnormality can be shortened, and the paper and the apparatus can be prevented from being damaged due to the abnormality.

Since the control means of the present invention controls the paper transport speed of the paper transport member based on the pressure detected by the pressure-sensitive body, it is possible to reliably control the optimal paper transport speed according to the paper. .

The control means of the present invention compares the detected pressure at the time of sheet conveyance by the pressure-sensitive element with a pressure range set in advance based on the usable sheet type to thereby determine the sheet type, abnormal conveyance, and foreign matter. The presence / absence is determined and the conveyance of the sheet is controlled.
Further, the control means calculates an average value of the detected pressures of the plurality of pressure-sensitive bodies at predetermined time intervals and a degree of variation of the pressure in the sheet surface from the average value, and is outside a predetermined range. Since the conveyance of the sheet is sometimes stopped, it is possible to more reliably prevent the sheet from being damaged or the apparatus from being damaged due to an abnormality.

According to the present invention, there is provided a pressure-sensitive paper feed roller comprising a roller portion and a roller shaft for pressing and contacting a sheet feed member to pinch and feed a sheet. Since the body is provided, it is possible to reliably detect a pressure change during sheet conveyance with a simple configuration.

The pressure-sensitive body of the present invention is made of pressure-sensitive rubber, and a plurality of such pressure-sensitive rubbers are provided so as to be electrically insulated from each other in the axial direction. Size and abnormality detection can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing Embodiment 1 of an image forming apparatus using a sheet conveying device of the present invention.

FIG. 2 is a cross-sectional view illustrating a second embodiment of a document reading apparatus using the sheet conveying device of the present invention.

FIG. 3 is a cross-sectional view illustrating a transport roller with a pressure-sensitive body of the paper transport apparatus of the present invention.

FIG. 4 is a perspective view illustrating a transport roller with a pressure-sensitive body of the paper transport apparatus of the present invention.

FIG. 5A is a cross-sectional view illustrating a state in which a sheet is conveyed by the sheet conveying apparatus of the present invention, and FIG. 5B is a plan view.

FIG. 6A is a plan view illustrating a pressure detection state during conveyance of a large sheet of paper in the sheet conveyance device of the present invention, and FIG. 6B is a plan view of a small sheet of paper in the sheet conveyance device of the present invention. It is a top view explaining the pressure detection state at the time of conveyance.

FIG. 7 is a flowchart illustrating a pressure detecting operation of the sheet conveying device of the present invention.

[Explanation of symbols]

 3 Paper Conveying Roller 3a Conveying Roller with Pressure Sensing Body 3b Conveying Roller 21 Roller Shaft 21a Detecting Element 22 Outer Shell Roller 22a Pressure Sensing Body

Continued on the front page F term (reference) 3F048 AA02 AA04 AA05 AB01 AB02 BA06 BA10 BA13 BA14 BB05 CC02 EA01 EB24 EB26 EB29 3F049 AA01 CA16 DA12 LA02 LA05 LA07 LB02 LB03

Claims (8)

[Claims] 1. A sheet conveying device comprising a pair of sheet conveying members for pinching and conveying a sheet, wherein the sheet conveying member is provided with a pressure-sensitive body for detecting a pressure when the sheet to be conveyed is pinched; A sheet transport device, further comprising control means for controlling the transport of the sheet based on the detected pressure of the body. 2. The sheet conveying device according to claim 1, wherein a plurality of the pressure-sensitive members are provided in a width direction of the sheet. 3. The apparatus according to claim 1, wherein said control means stops the conveyance of the sheet when the pressure information value based on the pressure detected by said pressure-sensitive element is out of a predetermined range. Paper transport device. 4. The sheet conveying apparatus according to claim 1, wherein said control means controls a sheet conveying speed of said sheet conveying member based on a pressure detected by said pressure sensitive member. 5. The apparatus according to claim 1, wherein the control means compares the pressure detected by the pressure-sensitive body when the paper is conveyed with a pressure range set in advance based on a usable paper type.
2. The sheet conveyance device according to claim 1, wherein the conveyance of the sheet is controlled by determining whether there is an abnormal conveyance or a foreign substance. 6. The control means calculates an average value of the detected pressures of the plurality of pressure-sensitive bodies at predetermined time intervals, and calculates a degree of variation in the pressure in the sheet from the average value. 3. The sheet transport device according to claim 2, wherein the transport of the sheet is stopped when the distance is outside the predetermined range. 7. A pressure-sensitive member for detecting a pressure at the time of nipping and transporting a sheet by the roller unit in a sheet transporting roller including a roller portion and a roller shaft for pressing and contacting the sheet transporting member to pinch and transport the sheet. A paper transport roller, comprising: 8. The pressure-sensitive body according to claim 7, wherein the pressure-sensitive body is made of a pressure-sensitive rubber, and a plurality of the pressure-sensitive rubbers are provided so as to be electrically insulated from each other in the axial direction. Paper transport roller.