JP2000264463A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device accurately informing the exchange time of carrier rollers. SOLUTION: The frequencies of use of carrier rollers 1, 2, 3 are counted, the thickness of sheets 6 stored in a sheet storage means 4 is detected by a sheet thickness detecting means, and the detected sheet thickness is compared with the reference sheet thickness. When the thickness of the sheets 6 carried by the carrier rollers 1, 2, 3 are different from the reference sheet thickness, based on the comparison result, and the counted using frequency is corrected according to the thickness of the sheets 6. The frequency of use when the carrier rollers 1, 2, 3 carry the reference sheets and the frequency of use corrected based on the thickness of the sheets 6 are totaled, the totaled frequency of use and the preset prescribed limit frequency of use of the carrier rollers 1, 2, 3 are compared to each other, and a display means displays the roller exchange display based on the comparison result.

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, and more particularly to detection of replacement timing of a plurality of conveying rollers provided in an image forming apparatus.

[0002]

2. Description of the Related Art In various image forming apparatuses such as a copying machine, a printer, a facsimile, and a printing machine, a sheet such as transfer paper, recording paper, or printing paper stored in sheet storage means is conveyed to an image forming unit. Many transport rollers are used to discharge a sheet on which an image is formed by the image forming unit.

For example, in a paper feeding section of an electronic copying machine,
A call roller that abuts on the uppermost transfer sheet set in a sheet cassette as a sheet storage unit and feeds the sheet out of the sheet cassette, and prevents double feed of the transferred transfer sheet while preventing
A pair of retard rollers for transporting a sheet of transfer paper toward a transfer unit is used.

By the way, the surface of such a transport roller wears with the lapse of use time, and if the roller is left unattended, a sheet such as a transfer sheet may be skewed or jammed. When it reaches, it needs to be replaced with a new one. Conventionally, when a counter for checking the number of copies of a copying machine counts a predetermined number of sheets, for example, 30,000, 80,000, or 100,000, a specialist serviceman calls a calling roller or ,
The replacement of the retard roller was to be replaced.

[0005]

However, in such a conventional image forming apparatus such as a copying machine, depending on the user, a large number of small-size transfer papers of A4 size or less are used, In some cases, a large number of large-size transfer papers are used, and the manner of use is various.

Here, for example, when a large-size transfer sheet is fed from a paper feed cassette, the rotation time of a call roller and the like is longer than when a small-size transfer sheet is fed.
Specifically, when the small-sized transfer paper of A4 size is fed and when only the large-sized transfer paper of A3 size is fed, the latter is the net rotation time of the call roller or the like. (Use time) is nearly doubled.

When a large amount of thick transfer paper is fed, a greater conveying force is required than when a normal thickness paper such as 64 g / m ² paper is fed. Etc., the service life is shortened.

Therefore, if the transport rollers are uniformly replaced when the number of copies reaches a predetermined number as in the prior art, the transport rollers that can still be used are replaced, or conversely, the transport rollers that exceed the limit are used. In some cases, the use of the roller must be continued, and there is a possibility that the transfer paper may be jammed or skewed.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has as its object to provide an image forming apparatus capable of accurately knowing the timing of replacing a transport roller.

[0010]

According to the present invention, there is provided a multi-conveying apparatus for conveying a sheet stored in a sheet storing means to an image forming section and then discharging the sheet on which an image is formed by the image forming section. In an image forming apparatus having a roller,
Sheet thickness detecting means for detecting the thickness of a sheet stored in the sheet storing means, and counting means for counting the number of times a predetermined conveying roller of the plurality of conveying rollers has been used,
A first comparing means for comparing the thickness of the sheet detected by the sheet thickness detecting means with a thickness of the reference sheet; and a thickness of the sheet conveyed by the predetermined conveying roller based on a comparison result of the first comparing means. When the reference sheet is different from the thickness of the reference sheet, a correction unit that corrects the number of times of use counted by the counting unit according to the thickness of the sheet, and a number of times of use of a predetermined conveyance roller when the reference sheet is conveyed. A totaling means for accumulating the number of times of use corrected according to the thickness of the sheet by the correcting means, and comparing the number of times of use accumulated by the accumulating means with a preset number of times of use of the predetermined transport roller. And a display control means for causing the display means to perform a roller replacement display based on the comparison result of the second comparison means. .

Further, the present invention provides an image forming apparatus comprising a plurality of conveying rollers for conveying a sheet stored in a sheet storing means to an image forming section and then discharging the sheet on which the image is formed by the image forming section. In the forming apparatus, a sheet thickness detecting unit that detects a thickness of a sheet stored in the sheet storing unit, a sheet size detecting unit that detects a size of the sheet, and a predetermined conveying roller of the plurality of conveying rollers. Counting means for counting the number of times of use, first correcting means for correcting the number of times of use counted by the counting means according to the size of the sheet detected by the sheet size detecting means, and detection by the sheet thickness detecting means A first comparing means for comparing the thickness of the sheet and a predetermined thickness of the reference sheet, based on a comparison result of the first comparing means, If the thickness of the sheet conveyed by the constant conveyance roller is different from the thickness of the reference sheet, the number of uses corrected by the first correction unit after being counted by the counting unit is determined according to the thickness of the sheet. Second correcting means for correcting, and accumulating means for accumulating a corrected use number of the predetermined conveying roller when the reference sheet is conveyed and a use number corrected again according to the sheet thickness by the second correcting means. And a second comparing means for comparing the corrected number of times of use accumulated by the accumulating means with a preset use limit number of the predetermined transport roller, based on a comparison result of the second comparing means, Display control means for causing the display means to perform a roller replacement display.

Further, according to the present invention, the sheet thickness detecting means includes a number of sheets conveyed, and a sheet height of the sheet stored in the sheet storing means when the number is conveyed. It is characterized in that it is configured to detect the thickness.

Further, the present invention is configured such that the sheet thickness detecting means detects the thickness of the sheet based on the amount of movement of the holding member for holding the sheet in the sheet thickness direction during the sheet holding and conveying. It is characterized by having.

Further, as in the present invention, the number of times of use of a predetermined conveying roller among a number of conveying rollers for conveying the sheet is counted by the counting means, and the sheet thickness detected by the sheet thickness detecting means is determined. The thickness is detected, and the thickness of the sheet detected by the sheet thickness detecting means is compared with the thickness of the reference sheet by the first comparing means. When the thickness of the sheet conveyed by the predetermined conveying roller is different from the thickness of the reference sheet based on the comparison result of the first comparing unit, the number of times of use counted by the counting unit is determined by the correcting unit in accordance with the sheet thickness. To correct. Further, the number of times of use of the predetermined conveying roller when the reference sheet is conveyed and the number of times of use corrected according to the thickness of the sheet by the correcting means are accumulated by the accumulating means, and the accumulated number of uses by the accumulating means is determined in advance. The set number of times of use of the predetermined conveying roller is compared with the set use limit number by the second comparing means, and based on the comparison result of the second comparing means, the display control means causes the display means to perform the roller replacement display.

[0015]

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

FIG. 1 is a schematic view showing a sheet feeding section of a copying machine as an example of an image forming apparatus according to a first embodiment of the present invention. In FIG. The cassette 5 is an elevating tray on which a large number of transfer papers 6, which are examples of sheets, are stacked. The elevating tray 5 is provided on the paper feed cassette 4 so as to be vertically movable.

Reference numeral 1 denotes a pickup roller which is an example of a transport roller for transporting the transfer paper 6 in contact with the transfer paper 6,
Reference numeral 2 denotes a paper feed roller, which is an example of a transport roller disposed downstream of the pickup roller 1 in the transport direction, and reference numeral 3 denotes a paper feed roller 2.
A separation roller which is an example of a conveyance roller which is pressed against the separation roller.
Then, the paper feed roller 2 and the separation roller 3
The transfer paper 6 conveyed from the pickup roller 1 is separated one by one and sent out to a copying machine main body (not shown).

In FIG. 1, reference numeral 7 denotes a tray height detecting section for detecting the height of the elevating tray 5, and the tray height detecting section 7 detects the height of the tray abutting near the rear end of the transfer paper 6. It has a detection lever 7a and a photo sensor 7b.

Here, the tray height detecting lever 7a
When the height of the uppermost surface of the transfer paper 6 on the elevating tray 5 becomes lower with respect to the pickup roller 1 as the paper feeding operation progresses, the transfer paper 6 rotates downward. When the tray height detection lever 7a rotates downward by a predetermined amount, the photo sensor 7b detects this and outputs a detection signal to the CPU 9.

Here, the CPU 9 controls the entire apparatus. When the detection signal is input from the tray height detection unit 7 as described above, the CPU 9 controls the lifting tray 5 via the control circuit 15 shown in FIG. A lifting motor (not shown) for raising and lowering is driven to raise the lifting tray 5 so that the height of the uppermost surface of the transfer paper 6 is again at a predetermined position.

When the height of the uppermost surface of the transfer paper 6 on the elevating tray 5 becomes lower than the pickup roller 1 by a predetermined amount as the paper feeding operation proceeds, the elevating tray 5 is raised each time. The transfer paper 6 can always be reliably fed. In the present embodiment, the displacement amount of the sheet height detected by the tray height detection unit 7 is set to, for example, 1 mm.

By the way, as shown in FIG.
In addition to the control circuit 15, R in which a control program is stored
OM13, R in which various data and tables are stored
The AM 14, the operation panel 12, and the sheet thickness detecting unit 11 are connected.

Here, the RAM 14 has, for example, a pickup roller 1, a paper feed roller 2, and a separation roller 3 (hereinafter, referred to as a separation roller 3).
In this embodiment, the use state of the feeding roller (hereinafter referred to as the first area) 14a, which is a totaling means for counting the number of sheet feeding operations, which is the number of times of use, and the lifting tray 5 rise. A provisional use count area (hereinafter, referred to as a second area) 14b, which is a counting means for counting the number of sheet feeding operations performed up to this point, is provided.

Further, a reference value, for example, 0.1 mm, which is a thickness of a reference sheet serving as a reference for the thickness of the transfer paper 6, is set in the RAM 14, and a life value corresponding to the use limit number of the feeding roller is set. "100,000 points" is set. The RAM 14 is supplied with a power supply voltage from a battery (not shown) even when the power supply is turned off. Further, the RAM 14 may be constituted by an EEPROM.

The sheet thickness detecting section 11, which is an example of sheet thickness detecting means, calculates the thickness of the transfer paper 6 from the count value of the second area 14b when the elevating tray 5 is raised, that is, a predetermined value. 1mm displacement of seat height
Is divided by the number of transfer papers 6 fed during that time, thereby detecting the thickness of the transfer paper 6.

The thickness information of the transfer paper 6 detected by the sheet thickness detection unit 11 is input to the CPU 9 and
The CPU 9 compares the thickness information with a set value (0.1 mm) stored in the RAM 14.

Here, when the detected thickness of the transfer paper 6 is larger than the set value, the value accumulated in the second area 14b is corrected according to the thickness of the transfer paper 6, and the first area 1b is corrected.
4a. When the thickness of the transfer paper 6 is smaller than the set value, the value accumulated in the second area 14b is accumulated in the first area 14a as it is.

Further, when updating the storage contents of the first area 14a in this way, the CPU 9 checks whether or not the value has reached the life value of "100,000", and "100,000"
Is reached, it is determined that it is time to replace the feed rollers that have reached “100,000”, for example, the pickup roller 1, the feed roller 2, and the separation roller 3, and a message as a display means on the operation panel 12 is displayed. The display unit 12a is controlled to display a guidance to that effect.

Next, the feed roller replacement display control operation of the CPU 9 configured as described above will be described with reference to the flowchart shown in FIG.

First, when the copy key 12b of the operation panel 12 is input, the CPU 9 drives the pickup roller 1, the paper feed roller 2 and the separation roller 3 via the control circuit 15, and the paper feed operation is started. .

At this time, when the previous paper feeding is completed,
It is determined whether the lifting tray 5 has risen (STEP 10).
0), when the lifting tray 5 is raised (STEP
100) After resetting the count value X ′ corresponding to the pickup roller 1, the paper feed roller 2 and the separation roller 3 in the second area 14b to 0 (STEP 101),
Each time the sheet feeding operation is performed, the count value X ′ is updated one by one (STEP 102).

If the elevating tray 5 has not been lifted (N in STEP 100), the count value X 'is updated one by one each time a sheet feeding operation is performed (STEP 102).
In the present embodiment, it is assumed that the thickness of the reference transfer paper 6 is 0.1 mm, and when the height displacement of the transfer paper 6 becomes 1 mm, the lifting tray 5 moves up. In this case, the number A of the transfer paper 6 which is a reference to be conveyed before the lifting tray 5 is raised is 10
It is a sheet.

Thereafter, the paper feeding operation is continued, and the height of the uppermost surface of the transfer paper 6 on the elevating tray 5 is lowered by a predetermined amount with respect to the pickup roller 1.
Rises (Y in STEP 103), the sheet thickness detection unit 11 performs a sheet thickness calculation process (STEP 104).

That is, the thickness of the transfer paper 6 is detected by dividing the preset sheet height displacement of 1 mm by the number of transfer papers 6 fed in the meantime. Here, if the thickness of the transfer paper 6 is 0.1 mm as a reference, the number of the supplied transfer papers 6 is 10, and the calculation result is 0.1 mm.
Becomes On the other hand, when the thickness of the fed transfer paper 6 is larger than the thickness of the reference sheet and the number of fed sheets is, for example, eight, the transfer paper 6 being fed is divided by 8 to obtain a thickness of 0.125 m.
m is detected.

Next, after calculating the thickness of the transfer paper 6 in this way, it is determined whether or not the thickness is larger than the set value (0.1 mm) stored in the RAM 14 (STE).
P105; first comparing means). When the value is larger than the set value (Y in STEP 105), a constant corresponding to the thickness, for example, when the thickness of the transfer paper 6 is 0.125 mm, 1.2 is accumulated in the second area 14b. Multiplied by the counted value X ′, and the value corrected in this manner is applied to the first area 14a.
(STEP 106; correction means).

If the thickness of the transfer paper 6 is equal to (or smaller than) the set value (N in STEP 105), the accumulated count value X 'of the second area 14b is integrated into the first area 14a as it is. (STEP 107).

Next, the CPU 9 determines whether or not the count value X has reached the life value of "100,000" when the storage contents of the first area 14a are updated as described above (S100).
If the count value has reached "100,000" (Y in STEP108), the replacement of the pickup roller 1, the feed roller 2, and the separation roller 3 whose count value X has reached "100,000" It is determined that the time has come, and guidance for roller replacement is displayed on the message display section 12a on the operation panel 12 (STEP 109; display control means).

When the feed roller whose life has expired is replaced, the count value of the first area 14a is cleared at the same time. If the number of copies is small, and the lifting tray 5 does not rise during one copy operation, the sheet feeding operation is terminated without updating the value of the first area 14a.

As described above, by correcting the number of times of feeding operation (the number of times of use) of the feeding roller according to the thickness of the transfer sheet 6, it is possible to accurately know the time for replacing the feeding roller.

The display contents of the message display section 12a may be always displayed so that a general user can always check, or only the service person may call the display contents in the service mode. According to the former method, a general user other than the service person can always know the wear state of the feeding roller.

When the latter method is adopted, if a telephone line is connected to a copying machine so that the count value of the first area 14a can be called by telephone in the service mode, the serviceman does not have to go to the user. Even so, it is possible to check the usage state of the feed roller up to the present, that is, the wear state.

Further, the set value of the life is not limited to "100,000", but a second set value smaller than that, for example, "90,000" is provided. If the count value reaches "90,000", it will be soon. If a warning message that the feed roller reaches the end of its service life is displayed, and a replacement display is performed when "100,000" is reached, the user can contact a service person in advance,
Alternatively, when the replacement work can be performed by itself, a feed roller for replacement can be prepared.

Next, a second embodiment of the present invention will be described.

FIG. 4 is a schematic diagram showing a sheet feeding section of a copying machine which is an example of the image forming apparatus according to the present embodiment. In FIG. 1, reference numerals 100, 101, and 102 denote three-stage upper and lower paper feed units having paper feed cassettes 30, 31, and 32, respectively, and the respective paper feed cassettes 30, 31 of the paper feed units 100, 101, and 102, respectively. , 32, a large number of transfer papers 36, 37, 38 having different sizes are stacked and set on the elevating trays 33, 34, 35.

Reference numeral 21 denotes a pickup roller that abuts on the A4 size transfer paper 36 set in the paper feed cassette 30 of the upper paper feed unit 100 and conveys the transfer paper 36.
Reference numeral 22 denotes a paper feed roller disposed downstream of the pickup roller 21 in the transport direction, and reference numeral 23 denotes a separation roller that presses against the paper feed roller 22. The transfer paper 36 conveyed from the pickup roller 21 is separated one by one by the paper feed roller 22 and the separation roller 23 and sent out to a main body (not shown).

Reference numeral 39 denotes a tray height detection unit for detecting the height of the lifting tray 33. The tray height detection unit 3
Reference numeral 9 denotes a tray height detecting lever 39a which comes into contact with the vicinity of the rear end of the transfer paper 36, and a photo sensor 39b.

Here, the tray height detecting lever 39a
The transfer paper 3 on the elevating tray 33 as the paper feeding operation proceeds
When the height of the uppermost surface of the pickup roller 6 becomes lower than that of the pickup roller 21, it rotates downward. Further, when the tray height detection lever 39a rotates downward by a predetermined amount, the photo sensor 39b detects this and outputs a detection signal to the CPU 9. The displacement of the sheet height detected by the tray height detection unit 39 is set to, for example, 1 mm.

Reference numeral 24 denotes a pickup roller which abuts on the A4R size (A4 landscape) transfer paper 37 set in the paper feed cassette 31 of the middle paper feed unit 101 and conveys the transfer paper 37; A paper feed roller disposed downstream of the roller 24 in the transport direction;
2 is a separation roller that is in pressure contact with 2.

Reference numeral 41 denotes a tray height detection unit for detecting the height of the lifting tray 34. The tray height detection unit 4
Reference numeral 1 denotes a tray provided with a tray height detection lever 41a which comes into contact with the vicinity of the rear end of the transfer paper 37, and a photo sensor 41b. The pickup roller 24, the paper feed roller 25, the separation roller 26, and the tray height detection unit 41
Performs the same operation as that of the upper sheet feeding unit 100.

Further, in FIG.
Reference numeral 28 denotes a pick-up roller which abuts on the A3-size transfer paper 38 set in the paper feed cassette 32 of No. 02 and conveys the transfer paper 38. Reference numeral 28 denotes a paper feed roller disposed downstream of the pickup roller 27 in the conveyance direction. Is the paper feed roller 28
Is a separation roller that is in pressure contact with the roller.

Reference numeral 43 denotes a tray height detecting unit for detecting the height of the elevating tray 35.
Reference numeral 3 is provided with a tray height detection lever 43a which comes into contact with the vicinity of the rear end of the transfer paper 38, and a photo sensor 43b. The pickup roller 27, the paper feed roller 28, the separation roller 29, and the tray height detection unit 43
Performs the same operation as that of the upper sheet feeding unit 100.

Further, in FIG.
This is a sheet conveying path provided downstream of each of the feeding rollers 22, 25, and 28 of 0, 101, and 102. An upstream portion of the sheet conveying path 47 is fed from the lower sheet feeding cassette 32. A transport roller pair 45 is provided as a positioning / transporting means for positioning and transporting the transfer paper 38.

In the middle part of the sheet conveying path 47, the transfer paper 37 fed from the middle paper cassette 31 is aligned and conveyed, and the transfer paper 38 fed from the lower paper cassette 32 is transferred. A transport roller 46 is provided as an alignment transport combined means for transporting. Then, each transfer paper 36, 37,
The sheet 38 is sent to the main body (not shown) via the sheet conveying path 47.

FIG. 5 shows the CPU 9 according to the present embodiment.
As shown in the figure, the CPU 9 includes a ROM 13 storing a control program, a RAM 14 storing various data and tables, an operation panel 12, a control circuit 15, a sheet thickness detecting unit. 11 and transfer papers 36, 3 provided in the paper feed units 100, 101, 102 and stored in the paper feed cassettes 30, 31, 32, respectively.
A sheet size detection unit 10 which is a sheet size detection unit for detecting the sizes of 7, 38 is connected.

The RAM 14 has a first area (usage count area) 14a, a second area (temporary use count area) 14b, and a sheet size table 14.
c and a sheet size index table 14d are provided. The sheet size detected by the sheet size detection unit 10 is stored in the sheet size table 14c.

In this embodiment, the sheet size detecting section 10 is provided in each of the sheet cassettes 30, 31, and 32 and detects the position of a separation claw (not shown) set according to the sheet size. Is used to detect the sheet size.

The sheet size index table 14d corrects the use time of the feed roller when conveying the transfer sheet of another size with respect to the use time of the feed roller when conveying the reference sheet size. The exponent is stored. In this embodiment, as shown in FIG. 6, an index (count increment) for each sheet size based on the B5 size is stored.

For example, when the sheet size is A4 (vertical), the use time is longer than when the B5 size is conveyed. , (210/182) × 1
00 = 115.

For sheets of other sizes, the same calculation is carried out. In the case of B5R (landscape), "141" and A
In the case of 4R (horizontal), it is "163", in the case of B4 (vertical), it is "200", and in the case of A3 (vertical), it is "231".

In the first area 14a, the usage status of the feeding roller, in this embodiment, the accumulation of the index corresponding to the sheet size and the index in consideration of the sheet thickness described later are accumulated and stored. It is supposed to be.

Further, the lifting tray 3 is provided in the second area 14b.
The number of sheet feeding operations performed until 3, 34, 35 rises is counted, and indices corresponding to the transfer sheets 36, 37, 38 fed for each sheet feeding operation are accumulated. ing.

The RAM 14 has a reference value which is a thickness of a reference sheet which is a reference of the thickness of the transfer paper 6, for example, a value of 0.1.
1 mm is set, "1 million points" is set as the life value corresponding to the use limit number of times of the feeding roller, and the count value of the first area 14a is set to "100
When "10,000" is reached, the CPU 9 determines the replacement time (lifetime) of the corresponding feed roller, and guides the content on the operation panel 12.

Next, the feed roller replacement display control operation of the CPU 9 configured as described above will be described with reference to the flowchart shown in FIG.

First, when the copy key 12b of the operation panel 12 is input, the CPU 9 controls the pickup rollers 21, 24, 27 and the paper feed rollers 22, 2 via the control circuit 15.
5, 28 and the separation rollers 23, 26, 29 are driven, whereby the sheet feeding operation is started.

At this time, the CPU 9 first sets the paper feed cassettes 30 and 3 in which the transfer paper corresponding to the key input is stored.
1 and 32 as well as the sheet cassettes 30 and 3
The sheet size is detected in accordance with a detection signal from the sheet size detection unit 10 provided in each of the first and second sheets (STEP 20).
0), the sheet size information is stored in the sheet size table 1
4c.

Next, at the end of the previous sheet feeding, the lifting tray 3
It is determined whether 3, 34, 35 have risen (STEP 2).
01), when the lifting trays 33, 34, 35 are raised (Y in STEP 201), the pickup rollers 21, 24, 27 and the sheet feeding rollers 22, 2, in the second area 14b.
After resetting the count values X 'corresponding to the separation rollers 5, 28 and the separation rollers 23, 26, 29 to 0 (STEP 20)
2) An index corresponding to the detected sheet size is read from the sheet size index table 14d (STEP 20).
3: first correction means). Then, every time a sheet feeding operation is performed, an index A corresponding to the sheet size is accumulated in the count value X '(STEP 204).

If the elevating trays 33, 34, 35 are not raised (N in STEP 201), the index A corresponding to the sheet size is accumulated in the count value X 'of the second area 14b every time the sheet feeding operation is performed. (Step 204).

For example, when it is determined that the A3 transfer paper 38 stored in the paper feed cassette 32 of the lower paper feed unit 102 is fed, the CPU 9 sets the sheet size index table 1
The index "231" for the A3 size is read from 4d, and the index "231" is cumulatively added to the area for the feeding roller of the lower sheet feeding unit 102 of the second area 1b.

The paper feed cassette 3 of the middle paper feed unit 101
When it is determined that the A4R transfer paper 37 stored in No. 1 is fed, the index “163” for the A4R size is read from the sheet size index table 14 d, and the second index is read.
The index “163” is cumulatively added to the area for the feed roller of the middle sheet feeding unit 101 of the area 1b.

The sheet cassette 3 of the upper sheet feeding section 100
If it is determined that the A4 transfer paper 36 stored in the sheet feeder 0 has been fed, the CPU 9 reads the index “141” for the A4 size from the sheet size index table 14d, and reads the index “141” for the upper area of the second area 1b. The index “141” is cumulatively added to the area for 100 feed rollers.

Next, assuming that the paper feed cassette 32 of the lower paper feed unit 102 has been selected by key input, for example.
Thereafter, the sheet feeding operation is continued, and the height of the uppermost surface of the transfer paper 38 on the elevating tray 35 is lowered by a predetermined amount with respect to the pickup roller 1 and the elevating tray 35 is raised (Y in STEP 205). The thickness detector 11 performs a sheet thickness calculation process (STEP 206).

That is, the thickness of the transfer sheet 36 is detected by dividing the preset sheet height displacement of 1 mm by the number of transfer sheets 36 fed in the meantime. Here, if the thickness of the transfer paper 36 is 0.1 mm as a reference, the number of the supplied transfer papers 36 is 10, and the calculation result is 0.1 mm.

On the other hand, for example, when the thickness of the fed transfer paper 36 is thicker than the reference sheet and the number of fed sheets is, for example, eight, the thickness of the fed transfer paper 6 is reduced to zero by dividing by eight. .
It detects that it is 125 mm.

Next, after calculating the thickness of the transfer paper 38 in this way, it is determined whether or not the thickness is larger than the set value (0.1 mm) stored in the RAM 14 (STE).
P207; first comparing means). When the value is larger than the set value (Y in STEP 207), a constant corresponding to the thickness, for example, when the thickness of the transfer paper 6 is 0.125 mm,
1.2 is the count value X ′ accumulated in the second area 14b
And the value corrected in this way is integrated in the first area 14a (STEP 208; second correction means).

If the thickness of the transfer paper 6 is equal to (or smaller than) the set value (N in STEP 207), the accumulated count value X 'of the second area 14b is integrated as it is in the usage status count area. (STEP 209).

Next, when the CPU 9 updates the storage contents of the first area 14a as described above, it determines whether or not the value X has reached the life value of "1,000,000" (STEP 9).
210; second comparing means), when the count value has reached “1,000,000” (Y in STEP 210), the count value X is “10”.
It is determined that it is time to replace the pickup roller 27, the paper feed roller 28, and the separation roller 29, which has reached "0,000", and guidance for roller replacement is displayed on the message display section 12a on the operation panel 12 (STEP 211; display control). means).

When the supply roller whose life has expired is replaced, the count value of the first area 14a is cleared at the same time. If the number of copies is small, and the lifting tray 5 does not rise during one copy operation, the sheet feeding operation is terminated without updating the value of the first area 14a.

As described above, the thickness of the transfer paper 6 and the transfer paper 6
By correcting the number of times of feeding operation (the number of times of use) of the feeding roller according to the size of the feeding roller, it is possible to accurately know the time to replace the feeding roller.

The display contents of the message display section 12a may be displayed at all times so that the general user can always check the contents, or only the service person may call the display contents in the service mode. . According to the former method, a general user other than the service person can always know the wear state of the feeding roller.

When the latter method is adopted, if a telephone line is connected to the copying machine so that the count value of the first area 14a can be called by telephone in the service mode, the serviceman does not have to go to the user. Even so, it is possible to check the usage state of the feed roller up to the present, that is, the wear state.

Further, the set value of the life is not limited to "1,000,000", but a second set value smaller than that, for example, "90".
When the count value reaches "900,000", a warning display indicating that the feed roller will soon reach the end of its life is displayed, and when the count value reaches "1,000,000", a replacement display is performed. Then, when the user contacts the service person in advance or can perform the replacement operation by himself, a replacement feed roller can be prepared.

Next, a third embodiment of the present invention will be described.

FIG. 8 is a schematic diagram showing a paper feeding unit of a copying machine which is an example of the image forming apparatus according to the present embodiment. In the figure, reference numeral 54 denotes a paper feed cassette, and 55 denotes an elevating tray on which a large number of transfer papers 60 are stacked.
Reference numeral 5 is provided so as to be movable up and down with respect to the sheet cassette 54.

Reference numeral 51 denotes a pickup roller which abuts on the transfer paper 6 and conveys the transfer paper 60. Reference numeral 52 denotes a paper feed roller disposed downstream of the pickup roller 51 in the conveyance direction.
Reference numeral 3 denotes a separation roller that presses against the paper feed roller 52. Then, the paper feed roller 52 and the separation roller 53 form
The transfer paper 60 conveyed from the pickup roller 51 is 1
Each sheet is separated and sent out to a main body (not shown).

In the same drawing, reference numerals 56 and 57 denote a pair of rollers which are provided further downstream of the paper feed roller 52 and are sandwiching members formed of plastic or the like. , The lower roller 57 is the shaft 5
7 is a stationary roller rotatably held by a device main body (not shown) via 7a. On the other hand, the upper roller 56 is a moving roller that is rotatably held by a device main body (not shown) and that can be brought into contact with and separated from the stationary roller 57, and is constantly moved by an urging spring 59 as shown in FIG. It is in pressure contact with the lower roller 57.

When the transfer paper 60 enters between the two rollers 56 and 57 and is nipped and conveyed, the moving roller 5
Numeral 6 is displaced in a direction away from the stationary roller 57 in accordance with the thickness of the transfer paper 60 against the urging spring 59.

Reference numeral 58 denotes a contactless potentiometer provided in association with the position of the pair of rollers 56 and 57. The potentiometer 58 includes a pair of rollers 56 and 57.
When the transfer paper 60 is nipped and conveyed in the meantime, if the gap between the pair of rollers 56, 57, that is, the distance between the pair of rollers 56, 57 is increased in accordance with the thickness of the transfer paper 60, the mechanical force is accordingly increased. , And the amount of the displacement is transmitted to the CPU 9.

In this embodiment, although not shown, a paper feed unit configured as shown in FIGS. 8 and 9 is provided in three upper and lower stages (see FIG. 4).

Next, the feed roller replacement display control operation of the CPU 9 configured as described above will be described with reference to the flowchart shown in FIG.

First, when the copy key 12b of the operation panel 12 is input, the CPU 9 drives, for example, the pickup roller 51, the paper feed roller 52, and the separation roller 53 shown in FIG. The operation starts.

At this time, the CPU 9 first responds to a detection signal from a sheet size detection unit 10 provided in a sheet cassette in which transfer paper corresponding to key input is stored, for example, a sheet cassette 54 shown in FIG. Then, the sheet size is detected (STEP 300), and this sheet size information is input to the sheet size table 14c.

Next, the thickness of the transfer paper 60 being fed is detected based on a signal from a potentiometer 58 provided on a pair of rollers 56 and 57 constituting the sheet thickness detection means, and the thickness of the transfer paper 60 is detected. Is the set value stored in the RAM 14,
For example, it is determined whether it is larger than 0.1 mm (ST
EP301; first comparing means).

If it is larger than the set value (S
(Y in STEP 301), the value accumulated in the second area 14b is cleared (STEP 302), and the index for the sheet size of the sheet cassette 54 is read from the RAM 14 (S30).
(Step 303) The index is accumulated in the second area 14b (Step 304).

When all the papers have been fed, the coefficient 1.2 considering the thickness of the transfer paper 6 is counted in the second area 14b in the same manner as in the first and second embodiments. The value X ′ is multiplied, and the corrected value is integrated in the first area 14a (STEP 305).

On the other hand, when the thickness of the transfer paper 6 is equal to (or smaller than) the set value (N in STEP 301), the index for the sheet size of the paper feed cassette 54 is stored in the RAM 14.
(STEP 306), and accumulates in the first area 14a (STEP 307).

Next, when updating the storage content of the first area 14a in this way, the CPU 9 determines whether or not the count value X has reached the life value "1,000,000" (STEP 308; 2 comparison means), when the count value has reached “1,000,000” (Y in STEP 308), the pickup roller 51 whose count value has reached “1,000,000”,
It is determined that it is time to replace the sheet feed roller 52 and the separation roller 53, and guidance for roller replacement is displayed on the message display section 12a on the operation panel 12 (STEP 309; display control means).

When the feed roller whose life has expired is replaced, the count value of the first area 14a is cleared at the same time. If the number of copies is small, and the lifting tray 5 does not rise during one copy operation, the sheet feeding operation is terminated without updating the value of the first area 14a.

As described above, the thickness of the transfer paper 60 is
And the number of sheet feeding operations (the number of times of use) of the feed roller is corrected in accordance with the detected thickness of the transfer paper 60, thereby accurately replacing the feed roller. You can know.

[0099] The display contents of the message display section 12a may be displayed at all times so that a general user can always confirm, or the display contents may be called only by a service person in the service mode. . According to the former method, a general user other than the service person can always know the wear state of the feeding roller.

When the latter method is adopted, if a telephone line is connected to the copying machine so that the count value of the first area 14a can be called by telephone in the service mode, the service person does not have to go to the user. Even so, it is possible to check the usage state of the feed roller up to the present, that is, the wear state.

Furthermore, the set value of the life is not limited to "1,000,000", but a second set value smaller than that, for example, "90".
When the count value reaches "900,000", a warning display indicating that the feed roller will soon reach the end of its life is displayed, and when the count value reaches "1,000,000", a replacement display is performed. Then, when the user contacts the service person in advance or can perform the replacement operation by himself, a replacement feed roller can be prepared.

[0102]

As described above, according to the present invention, it is possible to accurately know the time to replace the transport roller by correcting the number of times the transport roller is used according to the sheet thickness and the sheet size. As a result, it is possible to prevent the occurrence of the conventional problem caused by the uniform exchange of the transport roller.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a sheet feeding unit of a copying machine as an example of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a control block diagram of the copying machine.

FIG. 3 is a flowchart illustrating a feed roller replacement display control operation of a CPU of the copying machine.

FIG. 4 is a schematic diagram illustrating a sheet feeding unit of a copying machine as an example of an image forming apparatus according to a second embodiment of the present invention.

FIG. 5 is a control block diagram of the copying machine.

FIG. 6 is a table showing indices corresponding to sheet sizes stored in a RAM of the copying machine.

FIG. 7 is a flowchart illustrating a feed roller replacement display control operation of a CPU of the copying machine.

FIG. 8 is a schematic diagram showing a sheet feeding unit of a copying machine as an example of an image forming apparatus according to a third embodiment of the present invention.

FIG. 9 is a control block diagram of the copying machine.

FIG. 10 is a flowchart illustrating a feed roller replacement display control operation of a CPU of the copying machine.

[Explanation of symbols]

1,21,24,27,51 Pickup roller 2,22,25,28,52 Paper feed roller 3,23,26,29,53 Separation roller 4,30,31,32,54 Paper feed cassette 6,36, 37, 38, 60 Transfer paper 7, 39, 41, 43 Tray height detection unit 9 CPU 10 Sheet size detection unit 11 Sheet thickness detection unit 12 Operation panel 12a Message display unit 14 RAM 14a Usage count area 14b Temporary use status count Area 14c Sheet size table 14d Sheet size index table 56, 57 Roller 58 Potentiometer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H027 DA41 DC02 DC19 GA30 HB02 HB16 3F048 AA01 BA05 BA06 BB02 BC04 CA02 DA06 EB24 3F343 FA02 FB01 FC22 GA01 GB01 GC01 GD01 JA01 JD34 KB06 LA04 MA03 MA15 MA27 MA43 MB15 MB19 MC28

Claims (4)

[Claims] 1. An image forming apparatus comprising: a plurality of conveying rollers for conveying a sheet stored in a sheet storing unit to an image forming unit and then discharging the sheet on which an image is formed by the image forming unit. Sheet thickness detecting means for detecting the thickness of a sheet stored in the sheet storing means; counting means for counting the number of times a predetermined transport roller of the plurality of transport rollers has been used; and detection by the sheet thickness detecting means. First comparing means for comparing the thickness of the obtained sheet with the thickness of the reference sheet, and based on the comparison result of the first comparing means, the thickness of the sheet conveyed by the predetermined conveying roller is equal to the thickness of the reference sheet. If different, a correction means for correcting the number of times of use counted by the counting means in accordance with the thickness of the sheet; and a predetermined conveyance when the reference sheet is conveyed. Accumulating means for accumulating the number of times the roller has been used and the number of times of use corrected according to the thickness of the sheet by the correcting means; the number of times of use accumulated by the accumulating means; The second to compare with the limit number
An image forming apparatus comprising: a comparison unit; and a display control unit that causes a display unit to perform a roller replacement display based on a comparison result of the second comparison unit. 2. An image forming apparatus comprising: a plurality of conveying rollers for conveying a sheet stored in a sheet storing unit to an image forming unit and then discharging the sheet on which an image is formed by the image forming unit. A sheet thickness detecting unit that detects a thickness of a sheet stored in the sheet storing unit; a sheet size detecting unit that detects a size of the sheet; and a number of times of use of a predetermined transport roller among the multiple transport rollers. Counting means for counting; first correction means for correcting the number of times of use counted by the counting means in accordance with the size of the sheet detected by the sheet size detection means; The first comparing the thickness with the thickness of a preset reference sheet
Comparing means, based on a comparison result of the first comparing means, when the thickness of the sheet conveyed by the predetermined conveying roller is different from the thickness of the reference sheet, after counting by the counting means,
Second correction means for correcting the number of uses corrected by the first correction means in accordance with the thickness of the sheet; corrected number of uses of a predetermined transport roller when the reference sheet is transported, and the second correction Means for accumulating the number of times of use corrected again according to the thickness of the sheet by means, and the number of times of use corrected and accumulated by the means for accumulating, and the number of times of use of the predetermined conveying roller set in advance, An image forming apparatus comprising: a second comparing unit that performs comparison; and a display control unit that causes a display unit to perform a roller replacement display based on a comparison result of the second comparing unit. 3. The sheet thickness detecting means detects a thickness of the sheet based on a number of sheets conveyed and a change in height of a sheet stored in the sheet storing means when the number of sheets is conveyed. The image forming apparatus according to claim 1, wherein the image forming apparatus is configured to perform the following. 4. The apparatus according to claim 1, wherein the sheet thickness detecting means detects the thickness of the sheet based on an amount of movement of the holding member for holding the sheet in the sheet thickness direction during the sheet holding and conveying. 3. The method according to claim 1, wherein
The image forming apparatus as described in the above.