JPH02144557A - Device abnormality detecting device and correcting device for image formation position of image forming device - Google Patents

Abstract

PURPOSE:To detect the abnormality of the image formation position in its early stage and to urge a user, etc., to perform proper processing by providing an original detecting means, a formed image detecting means, a distance difference calculating means, and a decision means. CONSTITUTION:This device is equipped with the original detecting means 28 which detects the distance from the starting point of the effective exposure scanning area of the image forming device to the starting point of an entry area on a document and the formed image detecting means 29 which detects the distance from the head of transfer paper to the starting point of an area where an image is formed in the entry area on the original. Further, the distance difference calculating means 312 calculates the difference between the distances detected by the original detecting means 28 and formed image detecting means 29 respectively and the decision means 315 outputs a warning signal when the difference exceeds a previously set permissible range. Consequently, the abnormality of the image formation position on transfer paper is detected in its early stage, and the user is urged to perform proper processing.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an abnormality detection device for detecting an abnormality in the position of an image formed on transfer paper in an image forming apparatus such as a copying machine, and The present invention relates to a correction device that performs correction.

[Conventional technology]

Generally, optical image forming devices such as electrophotographic copying machines are
The original placed on the original placing section is exposed and scanned by the optical system, and! The transfer paper is fed to a transfer position inside a@, and after transferring the image formed by the exposure scanning to the transfer paper, the transfer paper is discharged. At this time, a time difference is maintained between the start timing of the above-mentioned exposure operation and the start timing of the paper feeding operation according to the variable magnification conditions, and this allows the position of characters, etc. on the original document and the time difference on the transfer paper. Coincidence with the image forming position regarding the above-mentioned characters, etc. is attempted.

(Problem to be Solved by the Invention) As described above, even if the difference between the document exposure operation timing and the paper feeding timing is kept constant, the transfer timing may change depending on the quality of the transfer paper or the environment inside the copying machine. can be,
In particular, due to changes in the operating speed of the paper feeding mechanism and optical system due to aging due to long-term use, the leading edge of the transfer paper and the beginning of the area where images such as the above characters are formed on the transfer paper. The distance to the edge changes, causing a problem that the image is no longer formed at the correct position on the transfer paper.

As a means for detecting the leading edge misalignment of such a formed image, a sensing means such as a sensor switch is provided on the transfer paper ejection side of the image forming apparatus, and the position is adjusted depending on the timing at which this detection means detects the leading edge of the ejected transfer paper. It is possible to judge the misalignment, but the timing of ejecting the transfer paper changes depending on the separation conditions from the photoreceptor drum and variations in the conveyance speed of the transfer paper after separation. Even though the timing is appropriate and the image forming position on the transfer paper is good, there is a possibility that it will be erroneously detected as abnormal.

Furthermore, Japanese Patent Application Laid-Open No. 60-247659 discloses a device that detects the image density, etc. of the original and the image density, etc. of the copy, and stops the drive of the motor when an abnormality is found by comparing the two. However, this publication does not disclose any specific means for detecting abnormalities in image forming positions or correcting them.

In view of these circumstances, the present invention provides an abnormality detection device capable of early detecting an abnormality in the image forming position on transfer paper, and ii! An object of the present invention is to provide a correction device that can automatically correct an iI image forming position.

[Means to solve the problem]

The present invention provides an image forming apparatus that feeds a transfer paper to an image forming position, forms an image based on an image of a document on the transfer paper, and then discharges the transfer paper. a document detecting means for detecting a distance from a starting edge to a starting edge of a writing area in the manuscript; and a document detecting means for detecting a distance from the leading edge of the transfer paper to a starting edge of an ffi area in which an image of the writing area of the manuscript is formed. an image detection means, a distance difference calculation means for calculating the difference between the distances respectively detected by the document detection means and the formed image detection means, and a determination for outputting a warning signal when this difference exceeds a preset tolerance range. (Claim 1)

Further, the present invention feeds the transfer paper to an image forming position by starting the exposure operation of the original and the feeding operation of the transfer paper with a certain time difference, and forms an image based on the image of the original on this transfer paper. In an image forming apparatus that later discharges the transfer paper, there is provided a document detecting means for detecting the distance from the start end of the effective exposure scanning area in the image forming apparatus to the start end of the writing area on the document; Formed image detection means for detecting the distance to the starting edge of the area where the image is formed in the writing area of the manuscript, and the distances detected by the document detection means and the formed image detection means, respectively, for a preset number of transfer sheets. and a correction means for correcting the time difference between the exposure operation of the document and the feeding operation of the transfer paper based on this average value. 2).

Note that the above-mentioned "average value" is not limited to simply dividing the sum of each distance difference by the number of transfer sheets, but is also used as a representative value of each distance III difference to serve as a basis for determining abnormality detection or correction. Any value is sufficient. Further, the set number of sheets is not limited to calculating the average value every fixed number of sheets, but the interval between sheets may be reduced as the number of sheets of image formation increases.

[For production]

First, according to the apparatus according to claim 1, the distance from the starting end of the effective exposure scanning area in the image forming apparatus to the starting end of the writing area on the original document, and the distance from the leading edge of the transfer paper to the image writing area on the original document are as follows. The distance to the starting end of the formed area is detected, and if the difference between the detected distances exceeds a preset tolerance range, a warning signal is output.

Furthermore, according to the apparatus of claim 2, the time difference between the exposure timing of the document and the feeding timing of the transfer paper is corrected based on the average value of each distance difference obtained for a predetermined number of transfer paper sheets, and thereby, The image forming position on the transfer paper is automatically corrected.

〔Example〕

A first embodiment of the present invention will be described based on FIGS. 1 to 6.

The copying machine (image forming device W1) 1 shown in FIG. 2 has a contact glass 2 and a document holder 3 on its upper surface, an optical system in the upper part of the interior, and an image forming means in the lower part of the interior. .

The optical system includes a halogen lamp 4, a lamp reflector 5,
It is composed of a plurality of mirrors 61 to 64 and a lens 7, and at a predetermined position there is a timing switch 2 that detects that the halogen lamp 4 is at the exposure scan start position.
4 are arranged.

The halogen lamp 4, lamp reflector 5, and mirrors 61 to 63 are operated by an optical system drive motor 16 shown in FIG.
The contact glass 2 is connected to the contact glass 2, and is configured to perform exposure scanning of the document placed on the contact glass 2 by reciprocating a predetermined distance in response to the driving force of the motor 16. The control of the optical system drive motor 16 is performed by a motor control board 1 connected to the timing switch 24.
9 (FIG. 1) (details will be described later).

The image forming means includes a photosensitive drum 8 as shown in FIG.
, and its peripheral equipment includes a band*a position 9, a blank lamp 10, a current 11!1111, a transfer v&@12, a separation device 13, a cleaning device 14, and a static elimination lamp 15. A portion of the peripheral surface located between the blank lamp 10 and the developing device 11 is irradiated with an image of the document exposed and scanned by the optical system.

Also, on the transfer paper transport path, in order from the upstream side, there is a paper feed tray 21, a pair of transport rollers 211, and a paper feed cassette 22.
, a paper feed roller 221, a pair of registration rollers 17, a conveyor belt 23, a constant @ device 25, a pair of discharge rollers 26, and a discharge tray 27 are provided. Above registration roller pair 1
7 is connected to a main motor (not shown) via a resist clutch 18 shown in FIG. 1, and its operation is controlled by turning on/off the resist clutch 18.

In such a structure, the transfer paper stored in the paper feed cassette 22 (or the transfer paper inserted into the paper feed tray 21) is transferred to the paper feed roller 221 (or the transport roller pair 211).
) for a predetermined period of time after the timing switch 24 detects that the paper is primarily fed to the registration roller pair 17, the optical system starts exposing the document, and the halogen lamp 4 has come to the exposure scanning start position. After the lapse of time, the paper is secondarily fed to the photosensitive drum 8 by the registration roller pair 17.

Further, as a feature of the present invention, a document reading sensor (document detection means) 28 is attached to the lamp reflector 5 of the halogen lamp 4 integrally with the reflector 5, and a document reading sensor (document detecting means) 28 is attached to the lamp reflector 5 of the halogen lamp 4. A copy image reading sensor (formed image detecting means) 29 is disposed at a position in between.

Both sensors 28 and 29 are of a light reflection type integrally equipped with a light-emitting element and a light-receiving element, and the document reading sensor 28 is configured to operate as shown in FIG. 3(a) during exposure scanning by the optical system. The copy image reading sensor 29 detects the writing area A1 of characters, etc. on the document paper placed on the contact glass 2, and the copy image reading sensor 29 detects this area A1 when the discharge transfer paper S is ejected as shown in FIG. It is configured to detect an area (copy area) A2 on the transfer paper S where characters, etc. detected by the document reading sensor 28 are copied. That is, both the sensors 28 and 29 are arranged at positions corresponding to each other in the width direction of the original paper and the transfer paper S.

In addition, in order for the contact to detect the starting end of the effective exposure scanning area on the lath 2, that is, the area where exposure scanning of the document is actually performed by the optical system, the halogen lamp 4 must be at the exposure scanning start position. The above-mentioned timing switch 24 is provided to detect this.

The sensors 28, 29 are connected to an i-control device 30 as shown in FIG. This control device 30 includes a central control section 31, a document memory 32, a copy image memory 33, an I10 boat 34, and an A/D converter 35.
, 36, the document reading sensor 28 and the copy image II! Detection signals from the reading sensors 29 are input to the central control unit 31 via A/D converters 35 and 36, respectively. Based on this detection signal, the central control unit 31 controls the direction from the starting end of the effective exposure scanning area to the original! I
Distance Wig1 (
3(a)) and the distance 1192 from the leading edge of the transfer paper S to its copy area A2 (FIG. 3(b)),
The data are input to the original memory 32 and the copy image memory 33, respectively.

The central control unit 31 is also connected to the motor control board 19 and the registration clutch 18 via the I10 boat 34, and the timing of the paper feeding operation by the registration roller pair 17 and the document exposure operation by the optical system. It is configured to control the

FIG. 5 shows the timing chart. As shown in the figure, the main motor operates at the same time as the print key is turned on, and the optical system drive motor 16 operates after a predetermined period of time.
6 starts the halogen lamp 4 and passes through the exposure scanning start position, the registration clutch 18 is turned on after a certain time difference t, and the paper feeding operation by the registration roller pair 17 is started. There is. The above time difference t
is from the starting end of the effective exposure scanning area to the writing area A1 of the document.
The distance Qt (FIG. 3(a)) to the starting edge of the transfer paper S is set to match the distance (12 (FIG. 3(b)) from the leading edge of the transfer paper S to the copy area A2.

Furthermore, as a feature of the present invention, the central control section 31 has the following features:
A counting section 311 and a comparing section 31 as shown in FIG.
2, an average value calculation section 313 (hereinafter referred to as average value calculation means), and a correction value calculation section (correction means) 314.

The counting unit 311 includes the copy image reading sensor 29
The number of sheets of transfer paper detected is counted. The comparison unit 312 sequentially compares the distance Q1 stored in the document memory 32 and the distance Q2 stored in the copy image memory 33 at the time when a predetermined number of transfer sheets (200 sheets in this case) are detected. The purpose is to find the difference (ρ2-Q1), and the average value calculation section 313 calculates the difference (ρ2-Q1).
The average value Qa of the differences determined by 12 is determined.

Then, the correction value calculation unit 314 compares the absolute value lNa1 of the calculated average value Qa with a preset threshold value, and if the absolute value lNa1 is larger, the correction value calculation unit 314 adjusts the original value according to the average value Qa. This is to correct the time difference t between the exposure start timing and the transfer paper feeding timing. Specifically, when the average value ia is a positive number, the time difference t is extended by an amount corresponding to its absolute value, and when Qa is a negative number, the time difference t is extended by an amount corresponding to its absolute value. The above-mentioned time difference t is shortened by the same amount.

Next, the operation of this device will be explained with reference to the flowchart shown in FIG. First, the count number N of the number of transfer sheets is reset to O (step S1), and when the print key is operated in this state, the copying operation is started (step 82). In other words, the transfer paper in the paper feed cassette 22 or the paper feed tray 21 is one step up to the registration roller pair 17.
After the next sheet is fed, the control device 30 outputs a control signal to the motor control board 19 to control the motor tlJII.
The optical system drive motor 16 is operated based on the control of the substrate 19, and exposure scanning by the optical system is started.

After the timing switch 24 confirms that the halogen lamp 4 of this optical system has passed the exposure scanning start position, the control TM equipment 30 is transferred to the resist clutch 18 after a preset constant time difference t. A control signal is output, and the resist clutch 18 is turned on. This causes the pair of registration rollers 17 to operate, and the transfer paper is secondarily fed to the photosensitive drum 8.

At this time, in the optical system, the original reading sensor 28 that moves together with the lamp reflector 5 reads the original image (step S3), and on the downstream side of the fixed @ device 25, the copy image reading sensor 29 reads the original image. The copy image on the transferred paper is read (step 84).

The output signals of both sensors 28 and 29 at this time are shown in FIG.
) (b), but here, the time τ1 shown in FIG. This corresponds to the distance Q1 to the writing area A1, and this distance e1 corresponds to the document memory 32 of the ID device 30.
is memorized.

Moreover, the time τ2 shown in FIG. 4(b) is
) from the leading edge of the transfer paper S to the copy area A.
2, and this distance C2
is stored in the copy image memory 33.

After the copying operation for one sheet of transfer paper is completed in this manner, 1 is added to the current count number N (step S5), and the operations from step S2 onwards are repeated (No at step Sθ).

Then, when the number of detected transfer sheets reaches 200, that is, when the count number N reaches 200, (
(YES in step S6), the distance 1iQt stored for the past 200 sheets of transfer paper and the distance g2 are compared (
Step S7), the average value ia of the difference (Q2-Qt)
is calculated (step Ss). Step S9
If No>, the copying position is determined to be normal and the copying operation continues as it is, but if it exceeds the threshold (YES in step S9), the time difference t is increased by the amount corresponding to this average value Qa. is corrected (step 510)
.

Therefore, according to this device, the number of ejected transfer sheets is 2.
00 sheets, the position of the writing area A1 (Fig. 3 (a)) on the manuscript paper and the copy area A2 on the transfer paper S
((b) in the same figure) and the time difference t between the document exposure operation and paper feeding operation is automatically corrected based on the difference, so that the copying machine 1 can be used for a long time. Even when using the scanner, it is possible to continue copying the original image without positional deviation.

Next, a second embodiment will be described based on FIG. 7.

Central control section 31' of the control device 30' in this embodiment
is the comparison unit (distance difference calculation means) 3 shown in FIG.
12, an abnormality determination unit (determination means) that compares the absolute flAIQ2−Q11 of the distance m difference calculated by the comparison unit 312 with a preset tolerance value (equal to the above threshold value).
It is equipped with 315. Then, the absolute taIQ2-011 is calculated each time copying is performed for each transfer paper, and if this absolute value exceeds the allowable value, a warning signal is sent to the display unit 40 provided outside the copying machine main body 1. It is configured to print and warn.

According to such a device, the description order MA1 in the original ID
position and copy area iI on transfer paper! A shift in the position of tA2 can be detected at an early stage, thereby prompting appropriate processing such as confirmation of ejected copies and repair of the copying machine itself.

Note that the present invention is not limited to the embodiments described above, but can also take the following embodiments as examples.

(1) Image forming position correction shown in the first embodiment;
Both abnormality detections shown in the second embodiment may be performed in parallel. That is, while performing the operations shown in the flowchart of FIG. 6, the distance difference (Q2-ρ1) is calculated each time the copying operation for one sheet of transfer paper is completed, and an abnormality is detected based on this difference. It will be more effective if you do this. Further, the distance differences calculated for each sheet of transfer paper may be stored and the average value calculated after copying a predetermined number of sheets. In this case, as in the first embodiment, the distance Q1, It is not necessary to remember c2 itself.

(2) In each of the above embodiments, paper feeding is performed after the operation of the optical system. The present invention can also be applied to an apparatus configured to perform the above first.

(3) Each of the sensors 2B and 29 can be installed at any position as long as it can detect the images of the original and the transfer paper. For example, the original reading sensor 28 is connected to the mirror 6 of the optical system.
1, or the copy image reading sensor 29 may be disposed upstream of the fixing device 25. However, since the diagonal conveyance of the transfer paper is corrected to some extent by the pair of fixing rollers of the fixing device 25, if the copy image reading sensor 29 is provided below Fftim of the fixing device 25 as in the above embodiment, false detection due to the diagonal conveyance is possible. Suppress me! Il
It has the advantage of being able to

(4) In the embodiment described above, the timing switch 24 was provided to detect the starting end of the effective exposure scanning area.
Instead, the contact glass 2 etc. shown in FIG.
) may be applied, and the start end may be detected by the document reading sensor 28. Also, as mentioned above, the actual distance IIfft,
92, but the corresponding value, for example, detected time τ1. Even if τ2 is directly compared, the above-mentioned distance difference can be found indirectly.

(5) The output target of the warning signal by the abnormality detection device of the present invention may be set as appropriate, and in addition to the display unit 40 as in the second embodiment, for example, the warning signal may be output audibly using a speaker, a buzzer, etc. Alternatively, the main motor may be stopped automatically.

(6) The above embodiments are all based on the assumption that the brass of the manuscript is copied at the same size. However, when applied to an image forming apparatus equipped with an enlargement/reduction function, when forming an image by enlarging or reducing, It may not be activated and sampling for correction or abnormality determination may be performed only when forming an image at the same magnification, or the distance mρ1 may be corrected based on the copying magnification and then compared with the distance +22. .

(7) Regarding the correction R1ff of the present invention [Average! 1ilI
] is not limited to the value obtained by simply dividing the sum of the differences in each distance by the number of sheets as described above, but may be any value that serves as a basis for the above correction. For example, if you use a calculation that focuses on the distance difference found for the last 100 sheets of the 200 sheets of transfer paper, the correction will be made more in line with the current situation. be able to.

(8) In the first embodiment, first the calculated average value Qa
and the threshold ri, and only if the former exceeds the latter, then v
Although the R difference t was to be corrected, such a comparison was not performed and the value Qa1. :M may be used for correction.

(Effects of the Invention) As described above, according to the present invention, the following effects can be obtained.

First, in the apparatus according to claim 1, an image of the writing area of the original is formed from a distance from the same starting edge of the effective exposure scanning area in the image forming apparatus to the starting edge of the writing area of the original, and from the leading edge of the transfer paper. The image forming position is determined to be abnormal if the difference between these distances exceeds a preset tolerance range. It is possible to detect abnormalities at an early stage, which has the effect of prompting the user to take appropriate measures.

Furthermore, the apparatus according to claim 2 is configured to correct the time difference between the document exposure operation timing and the paper feeding operation timing based on the distance difference calculated for a preset number of transfer sheets. Therefore, by automatically correcting the deviation of one image forming position, it is possible to form an image at a good position for a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an image forming position correction device provided in a copying machine according to a first embodiment of the present invention, FIG. 2 is a sectional view showing the internal structure of the copying machine, and FIG. 3 (a> A perspective view showing a document placed on the contact glass of the copying machine.
Figure (b) is a plan view of transfer paper discharged from the copying machine;
FIG. 4 (a> is a waveform diagram of the output signal of the original 1B reading sensor installed in the same copying machine, and FIG. 4 (b) is a waveform diagram of the output signal of the B image reading sensor installed in the same copying machine, Fifth
FIG. 6 is a timing chart showing the relationship between exposure scanning timing and paper feeding timing of a document in the same copying machine, FIG. 6 is a flowchart showing the operation of the correction device, and FIG. 7 is image formation in a second embodiment of the present invention. FIG. 2 is a block diagram of a position detection device. 1... Copy 1m (iii image forming device), 2... Contact glass, '16... Optical system drive motor, 17.
... Registrar pair, 18... Registrar pair,
28... Original reading sensor (original detection means), 29.
...Copy image reading sensor (formed image detection means), 3
0°30'...control device, 31.31'...central control section, 311...counting section (average value calculation means) 31
2... Comparison section (distance difference terminal means and average value calculation means), 313... Average value calculation section (average value calculation means), 3
14... Correction value calculation section (correction means), 315... Abnormality determination section (judgment means), D... Document, A1... Writing area in document, S... Transfer paper, A2...・Copy area on transfer paper (area where the image of the writing area is formed), Ql...Distance from the starting edge of the effective exposure scanning area to the starting edge of the writing area, Q2...Copy area from the leading edge of the transfer paper Distance m to the starting edge of

Claims (1)

[Claims] 1. In an image forming apparatus that feeds a transfer paper to an image forming position, forms an image based on an image of a document on the transfer paper, and then discharges the transfer paper, the effective a document detecting means for detecting a distance from a starting edge of an exposure scanning area to a starting edge of a written area on the document; and a document detecting means for detecting a distance from a leading edge of the transfer paper to a starting edge of an area in which an image of the written area of the document is formed. A formed image detecting means for detecting the formed image, a distance difference calculating means for calculating the difference between the distances respectively detected by the original detecting means and the formed image detecting means, and a warning signal is generated when this difference exceeds a preset tolerance range. What is claimed is: 1. An abnormality detection device for an image forming position in an image forming apparatus, comprising: a determining means for outputting an output. 2. By starting the exposure operation of the original and the feeding operation of the transfer paper with a certain time difference, the transfer paper is fed to the image forming position, and after forming an image based on the image of the original on this transfer paper, An image forming apparatus for discharging the transfer paper includes a document detecting means for detecting a distance from a starting edge of an effective exposure scanning area in the image forming apparatus to a starting edge of a written area on the document; formed image detection means for detecting the distance to the starting edge of the area where the image of the writing area is formed, and the distance detected by the document detection means and the formed image detection means for a preset number of transfer sheets Image formation characterized by comprising: an average value calculation means for calculating an average value of the differences; and a correction means for correcting the time difference between the exposure operation of the document and the paper feeding operation of the transfer paper based on the average value. A correction device for an image forming position in an apparatus.