JPH11130296A - Sheet carrying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely replace a rotating roller and prevent the measurement failure of carrying speed of a document sheet by measuring the carrying speed of a sheet to be carried by the rotation of a roller member, and displaying the replacement of the roller member when the life of the roller member is judged. SOLUTION: A carrying speed measuring sensor 25 is provided on the upstream side of the carrying direction (arrowed direction B) of a document sheet S and substantially in the vertical center to the carrying direction in order to prevent the oblique traveling of the document sheet by the load of a rotating roller 251 in the carrying of the document sheet S. When the feeding number of the document sheet S is increased, and the life of the rotating roller 251 comes near, a slippage is generated between the rotating roller 251 and the document sheet S by the reduction in frictional coefficient of the rubber surface of the rotating roller 251, and the waveform of an encoder output is not constant. When it can be judged whether such a phenomenon is different from a sudden one, the life of the rotating roller 251 can be judged to replace the rotating roller 251.

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 used for an image processing apparatus such as a copying machine, a laser beam printer, a facsimile, and the like.

[0002]

2. Description of the Related Art Conventionally, as a sheet conveying device in an image processing apparatus such as a copying machine, a laser beam printer, a facsimile, a scanner, etc., a feeding roller and a separation belt for separating the sheet are provided to prevent double feeding of the conveyed sheet. In general, a comb-separated sheet conveying device arranged in a comb shape is generally used.

[0003] In the driving structure of the sheet separating / conveying unit of the comb-separation type, a driving force from a driving mechanism is input to a driving shaft of the separation belt, and the driving force is transmitted to a feeding roller via one idler gear. As a result, the separation belt and the feed roller rotate in the same direction to prevent double feeding of sheets. In addition, the rotation speed of the feed roller for separating and conveying is
The peripheral speed is set so as to match the sheet conveying speed.

However, in the sheet separating and conveying section of the image processing apparatus as described above, the feeding roller and the sheet slip due to a difference in the thickness of the sheet to be conveyed or the friction coefficient between the front and back surfaces, and the like. In some cases, the conveyance speed of the sheet may change, and the sheet may not be able to arrive at the reading position or the recording position at a regular time.

In the conventional example described above, the conveying speed of the sheet separating / conveying section is measured using a conveying speed measuring sensor, and if the speed is lower than a predetermined speed, the driving mechanism of the sheet separating / conveying section is increased. By controlling the speed, the transport delay due to the above-described slip is reduced, and the sheet can be transported to the reading position or the recording position at a regular time.

[0006]

However, in the sheet separating / conveying section having the above structure, if the friction coefficient of the surface of the rotating roller of the conveying speed measuring sensor is reduced due to a problem such as durability, the rotating roller and the sheet slip. As a result, the above-described conveyance speed measurement sensor may not be able to correctly measure the conveyance speed.

That is, when the rotating roller slips with respect to the sheet, the conveyance speed measurement sensor sometimes determines that the speed is lower than the actual conveyance speed. At this time, since the drive mechanism of the sheet separation and conveyance unit is controlled to increase in speed,
If the sheet arrives at the reading position earlier than the regular time or an excessive load is applied to the sheet separation and transport unit,
This also shortened its life.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a conveying means for conveying a sheet, and a conveying speed for measuring the conveying speed of the sheet conveyed by the conveying means by rotation of a roller member. A sheet conveying device having a measuring unit and a display unit for displaying that the roller member should be replaced when the roller member has reached the end of its life by the life determining unit; Thus, the life of the transport speed measuring means can be accurately determined and replaced.

According to another aspect of the present invention, there is provided a sheet conveying apparatus comprising: sheet conveying means for conveying a sheet; and conveying speed measuring means for measuring a conveying speed of the sheet conveyed by the sheet conveying means. In the apparatus, a life determining means for determining a life of the transport speed measuring means,
The present invention provides a sheet conveying apparatus having a conveying speed measuring unit determined to have reached the end of its life by the life determining unit, and a display unit for displaying that it should be replaced. Can be accurately determined, and the replacement can be performed, and the occurrence of measurement failure of the sheet conveyance speed or the like can be prevented from occurring.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view of the entire image reading apparatus according to the present invention. The operation of the image reading section 1 and the document transport section 2 of the image reading apparatus will be described with reference to this drawing.

Reference numeral 3 denotes a stacking tray for stacking the document sheets S. When an instruction to start image reading is given, the exposure lamp 4 of the image reading unit 1 is turned on to start preparation for image reading, and the sheet feeding unit 2 feeds. The operation starts.

Then, the stacking tray 3 is moved upward from the standby position detected by the lower limit sensor 5 until the uppermost original sheet S is detected to be in contact with the paper surface height sensor 6, and then stopped.

The original sheet S is sent out by the rotation of the pickup roller 7 in contact with the uppermost original sheet S.

The original sheet S sent from the stacking tray 3 is separated from unnecessary original sheets S by a separation unit 8, and only one original sheet S is imaged by a pull-out roller 9 and conveying rollers 10, 11, and 12. It is transported to the reading unit 1.

The image reading section 1 is provided with a mechanism for reading an image on the document sheet S. That is, at the image reading point 13, the exposure lamp 4 is turned on to irradiate the original sheet S, and the reflected light is guided to the lens 18 by the mirrors 15, 16, 17 via the contact lens 14, and the CCD sensor 19 The information is converted into an electric signal and subjected to image processing through a well-known amplifier circuit and the like.

Thereafter, the original sheet S is transported by the transport rollers 20,
The paper is further conveyed to the downstream side by 21 and 22 and discharged to the discharge tray 23.

The above series of operations is repeated until all the original sheets S are exhausted. When all the original sheets S are exhausted, the stacking tray 3 is lowered to the standby position, the reading operation is completed, and the exposure lamp 4 is turned off.

Here, reference numeral 24 denotes a leading edge detection sensor for detecting that the leading edge of the document sheet has reached the transport position, and is provided at a position separated from the stacking tray by a predetermined distance.

During the transport operation of the original sheet S, the loading tray 3
Is always kept constant.

A conveying speed measuring sensor 2 for measuring the conveying speed is provided on the uppermost original sheet S on the stacking tray 3.
The arrangement of the sensor 25 will be described below with reference to FIGS.

FIGS. 2 to 4 are views showing the configuration of the transport speed measuring sensor.

In FIG. 2, reference numeral 251 denotes a rotating roller which comprises a core portion 251a, a roller portion 251b made of rubber, a disk portion 251c, and a hole portion 251d.
Has holes 251d opened at predetermined intervals.

Reference numeral 252 denotes a rotation shaft of the rotation roller 251. The holder 252 is formed by details 252b and projections 252c shown in FIG.
53 rotatably supported.

The holder 253 has an opening 253b in which the rotating shaft 252 is rotatably supported, and a slit is formed in the hole 253b so that the rotating shaft 252 can be fitted therein. Is configured.

As a result, the rotating roller 251 can be detached from the holder 253 and can be replaced.

Reference numeral 254 denotes a photo sensor, which is a holder 253.
And detects the rotation of the disk 251c.

When the disk 251c is driven to rotate in response to the operation of transporting the document sheet S, an on / off signal is output to the CPU 26 by the photo sensor 254, whereby the transport speed of the document sheet S is reduced. Measured.

FIG. 5 is a perspective view showing the structure of a sheet feeding section around the pickup roller 7. As shown in FIG.

The configuration around the pickup roller 7 will be described with reference to FIG.

The pickup roller 7 is rotatably mounted on an arm 27.
It is rotatably attached to.

The driving force of the paper feed drive motor 31 is transmitted to the pickup roller 7 via drive belts 29 and 30.

Reference numeral 32 denotes a rotation support lever, which is rotatable about a shaft 33. The power of a vertical drive motor 35 is transmitted by a drive belt 34 to drive the pickup roller 7 up and down in the direction of arrow L. It is configured as follows. That is, when paper is not fed, the vertical drive motor 3
5, the rotation support lever 32 raises the arm 27 to hold the arm 27 at the standby position and feeds the paper.
Is to hold the arm 27 at the lower feeding position and feed the original sheet by bringing the pickup roller 7 into contact therewith.

Note that the above-described transport speed measuring sensor 25
In order to prevent skew caused by the load of the rotating roller 251 during the conveyance of the document sheet S, the upstream side of the conveyance direction (the direction of the arrow B) of the document sheet S
It is provided substantially at the center in the vertical direction.

Next, referring to FIG. 6 to FIG. 8, the rotation roller 251 of the above-mentioned conveyance speed measuring sensor 25 according to the present invention will be described.
Will be described in detail.

FIG. 6 is a diagram showing the configuration of a control circuit for determining the life of the rotating roller 251.

When a rotational drive command is given to the motor driver 31a by the CPU 26, the motor driver 3a
1a supplies a pulse signal to the paper feed drive motor 31 to drive the pickup roller 7 to rotate.

Thereafter, with the transport operation of the original sheet S,
The output of the conveyance speed measurement sensor 25 and the output of the leading end detection sensor 24 are taken into the CPU 26 and stored in the RAM 36. The ROM 37 stores a program shown in a flowchart described later.

FIG. 7 is a diagram showing output signals of the control circuit shown in FIG.

First, when a paper feed start signal is output from the CPU 26, a motor driver output pulse is output from the motor driver 31a to the paper feed drive motor 31, the pickup roller 7 is rotated, and the original sheet S on the stacking tray 3 is rotated. Is transported.

When the leading edge of the conveyed document sheet S reaches the leading edge detection sensor 24, the signal output value changes from low to high.

Here, for example, the distance X from the wall 3a of the stacking tray 3 to the leading edge detection sensor 24 is 40 mm, the diameter of the pickup roller 7 is 30 mm, and the feed driving motor 31
If the paper feed drive motor 31 rotates by 1.8 ° per pulse without any acceleration / deceleration from the pickup roller 7 to the pickup roller 7, the pickup roller 7 will be 0.47 mm per pulse (30 mm × π × 1.8 °). / Pulse $ 36
0 °) The original sheet S is conveyed and moved, and the leading end of the original sheet S is moved from the stacking tray 3 to the leading end detection sensor 2.
4, the paper feed drive motor 31
A pulse (40 mm ÷ 0.47 mm / pulse) is output.

The diameter of the rotating roller 251 of the transport speed measuring sensor 25 is 30 mm,
If the original sheet S is transported 40 mm from the top of the stacking tray 3 to the leading edge detection sensor 24, the rotation of the transport speed measurement sensor 25 The roller 251 is 152.8 ° (4
0 mm ÷ 30 mm ÷ π × 360 ゜).
5 times (1
(52.8 ° ÷ 30 °).

However, as described above, when the number of fed sheets of the original sheet S increases and the life is short, the friction coefficient between the rubber surface of the rotating roller 251 and the like is reduced, so that the distance between the rotating roller 251 and the original sheet S is reduced. Slip occurs. This state is shown by the encoder output 2 shown in FIG. 7. The waveform is not constant, and in a normal state, the original sheet S reaches the leading end detection sensor 24 by 40 mm.
, The encoder output 1 repeats high / low five times at a time, but only four times.

If it can be determined that such a phenomenon is different from a sudden one, it can be determined that the life of the rotating roller 251 has expired, and the above-mentioned problem can be solved by replacing the rotating roller 251.

A description will now be given of a flowchart for that purpose.

FIG. 8 is a flowchart for judging the life of the rotating roller of the transport speed measuring sensor, which is stored in the ROM 36 of the control circuit shown in FIG.

First, for example, assuming that the configuration of the transport speed measuring sensor 25 is set under the above-described conditions, the encoder output 1 repeats high and low five times during the distance X. It is stored in the ROM 37 as the allowable value 5. Although the allowable value stores the number of pulses, the width may be stored and the difference may be compared.

In consideration of the fact that the above-mentioned sudden phenomenon occurs at a probability of about 1 / 100,000, the case where the actual measured value of the encoder output differs from the allowable value by 3 or more times is considered. This is also set in the counter 38 as the number of times of life determination so that it is determined as a sudden and excluded. (Note that it is sufficient to make three determinations based on the probability of a sudden phenomenon occurring.)

When the start signal of the life judgment is input to the CPU 26, the life judgment flow chart shown in FIG. 8 starts, and in step 81, the actual measured value of the encoder output value and the allowable value 5 stored in the ROM 37 are entered. Compare with

Next, it is determined in step 82 whether or not the actually measured value of the encoder output value is different from the allowable value. If there is a difference, the flow advances to step 83 to perform a normal reading operation sequence and end. I do.

If there is a difference from the allowable value, step 84
In step 85, it is determined whether or not this counter value exceeds a threshold value (3). If the counter value exceeds the threshold value (3), the process returns to step 81 again. It is determined whether there is a difference from the allowable value.

If it is determined in step 85 that the counter value has exceeded the threshold value (3), step 8
6. The display 3 prompts the user to replace the rotary roller 251.
In step 87, the apparatus main body is stopped and the processing is terminated.
As a result, the operator and the service person can know the life of the rotating roller, and the roller can be replaced.

By the operation described above, it is possible to accurately judge the life of the rotating roller of the conveyance speed measurement sensor, distinguishing from a sudden phenomenon, and to prevent an excessive load from being applied to the sheet separation / conveyance section. Can be prevented.

[0055]

As described above, according to the present invention,
Since it is configured to accurately determine the life of the rotating roller of the conveyance speed measurement sensor and display a message urging the replacement,
Not only can the rotating roller be replaced accurately, but also it is possible to prevent the occurrence of measurement errors in the conveyance speed of the original sheet, etc., and it is impossible to use a driving mechanism for the sheet separation and conveyance unit. It is possible to prevent a heavy load from being applied.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an entire image reading apparatus according to the present invention.

FIG. 2 is a diagram showing a configuration of a conveyance speed measurement sensor according to the present invention.

FIG. 3 is a diagram showing a configuration of a conveyance speed measurement sensor according to the present invention.

FIG. 4 is a diagram showing a configuration of a conveyance speed measurement sensor according to the present invention.

FIG. 5 is a diagram showing a configuration around a pickup roller of the image reading apparatus of the present invention.

FIG. 6 is a diagram illustrating a configuration of a control circuit for determining the life of a rotating roller of a conveyance speed measurement sensor according to the present invention.

FIG. 7 is a diagram showing output signals of the control circuit shown in FIG. 6;

FIG. 8 is a view showing a flowchart for determining the life of a rotating roller of a conveyance speed measurement sensor according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image reading part 2 Document conveyance part 3 Stacking tray 4 Exposure lamp 5 Lower limit sensor 6 Paper surface height sensor 7 Pickup roller 8 Separation part 9 Extraction roller 10 Transport roller 11 Transport roller 12 Transport roller 13 Image reading point 14 Contact lens 15 Mirror 16 Mirror 17 Mirror 18 Lens 19 CCD 20 Transport roller 21 Transport roller 22 Transport roller 23 Discharge tray 24 Tip detection sensor 25 Transport speed measurement sensor 251 Rotary roller 252 Rotary axis 253 Holder 254 Photo sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G03G 21/00 510 G03G 21/00 510

Claims (10)

[Claims] A conveying unit that conveys the sheet, a conveying speed measuring unit that measures a conveying speed of the sheet conveyed by the conveying speed by rotation of a roller member, and a life determining unit that determines a life of the roller member. And a display unit for displaying that the roller member should be replaced when the life determining unit determines that the roller member has reached the end of its life. 2. The method according to claim 1, wherein the life determining unit includes a pulse generating unit configured to generate a pulse at predetermined time intervals while the roller member travels a predetermined distance, and determining whether the pulse generated by the pulse generating unit is different from an allowable value. 2. The sheet conveying apparatus according to claim 1, further comprising a determination unit that determines that the roller member should be replaced based on a life. 3. The apparatus according to claim 1, wherein the life determining means includes a pulse generating means for generating a pulse at predetermined time intervals while the roller member travels a predetermined distance, and determining whether the pulse generated from the pulse generating means has a difference from an allowable value. A determination unit that determines that the roller member should be replaced based on a service life by determining whether the roller member should be replaced by a predetermined number of times.
The sheet conveying device as described in the above. 4. The apparatus according to claim 3, further comprising stacking means for stacking sheets, wherein said transport speed measuring means is arranged on an uppermost sheet stacked on said stacking means.
3. The sheet conveying device according to 1. 5. A sheet conveying apparatus having a sheet conveying means for conveying a sheet and a conveying speed measuring means for measuring a conveying speed of a sheet conveyed by the sheet conveying means, wherein a life of the conveying speed measuring means is determined. A sheet conveying device, comprising: a life determining unit for determining whether or not the conveying speed measuring unit whose life has been determined by the life determining unit is to be replaced. 6. A light-emitting means for emitting light, a light-receiving means for receiving light from the light-emitting means,
6. A roller member which comes into contact with a sheet, rotates in accordance with the movement of the sheet, and blocks light from the light emitting means toward the light receiving means in a predetermined cycle.
The sheet conveying device as described in the above. 7. A light-emitting means for emitting light, a light-receiving means for receiving light from the light-emitting means,
A roller member that contacts the sheet and rotates in accordance with the movement of the sheet, and blocks light from the light emitting unit toward the light receiving unit in a predetermined cycle; and the life determining unit determines whether the roller member travels a predetermined distance. Determining whether or not the transport speed measuring means should be replaced by determining whether or not the number of on / off signals of light emitted by the rotation of the optical disc is different from an allowable value. Item 6. The sheet conveying device according to Item 5. 8. A light-emitting means for emitting light, a light-receiving means for receiving light from the light-emitting means,
A roller member that contacts the sheet and rotates in accordance with the movement of the sheet, and blocks light from the light emitting unit toward the light receiving unit in a predetermined cycle; and the life determining unit determines whether the roller member travels a predetermined distance. A predetermined number of times of determining whether the number of on / off signals of light emitted by the rotation of the light is different from an allowable value, thereby determining that the transport speed measuring means should be replaced. The sheet conveying apparatus according to claim 5, wherein 9. The apparatus according to claim 5, further comprising a stacking unit for stacking the sheets, wherein the conveying speed measuring unit is arranged on an uppermost sheet stacked on the stacking unit.
3. The sheet conveying device according to 1. 10. The sheet conveying apparatus according to claim 5, wherein said life determining means includes means for judging that the conveying speed measuring means should be replaced by judging the life of said roller member. apparatus.