JP3941393B2 - Correction method and setting method of conveyance abnormality detection means in image forming apparatus, and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for correcting an abnormality detection condition for detecting conveyance skew of a sheet by a conveyance abnormality detection unit in an image forming apparatus, a method for setting an abnormality detection condition for detecting a registration error, and an image forming apparatus.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, image forming apparatuses and the like have been provided with a conveyance abnormality detection device that detects skew of a sheet, registration deviation, and the like in order to accurately form an image on the sheet.
[0003]
The conveyance abnormality detection device that detects skew is provided with a plurality of edge detection sensors that detect the edge of the sheet in a direction orthogonal to the conveyance direction on the conveyance path (hereinafter referred to as the width direction). Is detected based on the detection timing shift amount (time difference) (hereinafter referred to as Conventional Example 1).
[0004]
The following configuration is disclosed as another conventional example of the conveyance abnormality detection device.
[0005]
For example, in Japanese Patent Application No. 9-346803 (hereinafter referred to as Conventional Example 2), a plurality of actuators that rotate around an axis when pressed by an end of a recording sheet are installed in the width direction. A configuration is disclosed in which the passage timing of the leading edge and the trailing edge of the recording paper is detected based on the rotation timing. Therefore, the passage time of the recording paper in each of the plurality of actuators can be obtained, and an abnormality at the leading edge or the trailing edge of the recording paper can be detected by comparing with the passage time at the normal time.
[0006]
In Japanese Patent Application No. 10-4738 (hereinafter referred to as Conventional Example 3), two sensors that are offset along the paper conveyance direction and the width direction are arranged, and one sensor is the leading edge of the paper. One counter is used to measure the elapsed time from when the other sensor is detected until the other sensor detects the leading edge of the paper. A configuration is disclosed in which it is determined that the sheet is not skewed if the count value is equal to the time for transporting the sheet by the sensor interval.
[0007]
Furthermore, a conveyance abnormality detection device that detects registration deviation is disposed at a predetermined position on the conveyance path, and the registration error is determined by comparing the elapsed time from the output timing of the reference signal to the time when the sheet passes the sensor and the set time. Detect deviation.
[0008]
[Problems to be solved by the invention]
However, as in conventional examples 1 and 2, when a conveyance abnormality is detected based on the amount of deviation in detection timing provided in a plurality of detection sensors in the width direction, it is detected based on the detection sensor mounting error or sensitivity difference. There is a possibility that the amount of timing deviation becomes inaccurate and erroneously detects a conveyance abnormality.
[0009]
In addition, even when the detection sensor is offset in the transport direction as in the conventional example 3, the transport error is detected by comparing with the transport time based on the sensor interval. There was a risk of false detection due to the above.
[0010]
Further, even in a conveyance abnormality detection device that detects registration deviation, there is a possibility that erroneous detection may occur due to an attachment error or a difference in sensor sensitivity.
[0011]
Therefore, as a countermeasure against such erroneous detection, the operator performs test printing before using the conveyance abnormality detection device, measures the detection timing of a plurality of sensors, and visually checks the skew amount of the discharged paper. The detection timing is corrected by measuring. However, even if correction is made once, it is necessary to perform test printing again for confirmation. If there is an error, it is necessary to perform test printing again and make settings, which is complicated.
[0012]
Accordingly, in order to solve the above inconveniences, an object of the present invention is to provide a correction method and a setting method of an abnormality detection unit of an image forming apparatus and an image forming apparatus which can correct an error easily and accurately.
[0013]
[Means for Solving the Problems]
According to the first aspect of the present invention, in the image forming apparatus, the sheet detected by the plurality of edge detection means arranged in a straight line at a predetermined interval in the width direction orthogonal to the sheet conveyance direction on the conveyance path. A correction method for a conveyance abnormality detection unit that detects a sheet conveyance abnormality based on a deviation amount of an edge detection timing, wherein each of the edge detection units detects an edge of a sheet conveyed on a conveyance path. A plurality of the same reference images are formed at the same timing by the image forming unit at a position on the sheet corresponding to the position where the end detection unit is disposed in the width direction of the conveyance path in the first step. A plurality of measuring means are mounted at a position corresponding to the position where the edge detecting means is disposed in the width direction in the transport path downstream of the image forming means in the second step, and the edge of the paper A third step of the measuring means to pass time is measured until the reference image passes from the shift amount detection timing by a plurality of said edge detection means,
The amount of deviation of the passing time by a plurality of measuring means is obtained, and the amount of deviation of the detection timing is calculated. , Deviation amount of the detection timing and deviation amount of the passage time And a fourth step of changing an abnormality detection condition of the conveyance abnormality detection means so as to detect a conveyance abnormality of the sheet based on a value obtained by adding or subtracting the difference between the two.
[0014]
The operation of the first aspect of the invention will be described.
[0015]
A plurality of edge detection means detect the edge of the sheet conveyed along the conveyance path. Further, the conveyed paper forms the same reference image at the same timing by the image forming means at the position on the paper corresponding to the position of the edge detecting means in the width direction, and the paper passes through the measuring means. Thus, the passing time from the edge of the sheet to the reference image is measured.
[0016]
Here, when the paper is skewed, the edge of the paper arrives at each measuring means at different timings, but the reference image arrives at the same timing. Therefore, the shift amount (time difference) due to skewing is accurately detected based on the shift amount (time difference) of the passage time by the measuring means. On the other hand, the deviation amount (time difference) due to the detection timing by the edge detection means includes the detection timing deviation amount due to the attachment error of the edge detection means and the sensitivity difference, in addition to the detection timing deviation due to the skew of the paper. ing.
[0017]
Therefore, the correction means obtains a deviation amount due to a mounting error or a sensitivity difference (difference between both deviation amounts) by obtaining a difference between the detection timing deviation amount and the passage time deviation amount, and the detection timing deviation amount is calculated as the both deviations. The abnormality detection condition of the conveyance abnormality detection means is changed so as to detect the conveyance abnormality of the sheet based on a value obtained by adding or subtracting the difference between the amounts. Accordingly, it is possible to change the setting so that the abnormality detection unit of the paper conveyance device detects abnormality based on the deviation amount based only on conveyance abnormality due to skew.
[0018]
That is, the abnormality detection condition of the conveyance abnormality detection means can be corrected easily and accurately.
[0019]
According to the second aspect of the present invention, in the image forming apparatus, the registration deviation is detected based on the elapsed time from the reference timing to the edge detection timing of the sheet detected by the edge detection means disposed on the conveyance path. A method for setting a conveyance abnormality detection unit, the first step of detecting an elapsed time from the reference timing until the end of the sheet conveyed on the conveyance path by the edge detection unit is detected, and the conveyance A second step in which the image forming means forms a reference image at a predetermined timing at a position on the paper corresponding to the position where the end detecting means is disposed in the width direction of the path; and downstream of the image forming means Measuring means is mounted at a position corresponding to the position where the edge detecting means is disposed in the width direction in the conveyance path on the side, and the reference image is formed from the edge of the paper. The third step in which the measuring means measures the passing time until the time passes until the difference between the passing time and the theoretical passing time is obtained, and a registration shift is detected based on the time obtained by adding or subtracting the difference to the elapsed time. And a fourth step of setting an abnormality detection condition of the conveyance abnormality detection means.
[0020]
The operation of the second aspect of the invention will be described.
[0021]
The edge detection means detects the edge of the sheet conveyed along the conveyance path. Further, the conveyed paper forms a reference image at a predetermined timing by the image forming means at a position on the paper corresponding to the position of the edge detecting means in the width direction, and the paper passes through the measuring means. The transit time from the edge of the paper to the reference image is measured.
[0022]
An abnormality detection condition is set so as to detect a registration deviation based on a value obtained by adding or subtracting the difference between the passage time and the theoretical passage time calculated from the sheet conveyance speed. That is, the difference corresponds to a registration deviation, and a passage time (reference passage time) with no registration deviation can be set by adding or subtracting the difference to the passage time. That is, the abnormality detection condition of the conveyance abnormality detection means for detecting registration deviation can be set with high accuracy.
[0023]
The invention according to claim 3 is characterized in that the conveyance abnormality detection condition of the conveyance abnormality detection means is corrected by the correction method according to claim 1.
[0024]
The operation of the third aspect of the invention will be described.
[0025]
Since the skew detection condition is accurately corrected by the correction method according to claim 1, the conveyance abnormality detection unit is not affected by the sensitivity of the edge detection unit and the mounting error, and the conveyance abnormality detection unit performs conveyance abnormality such as sheet skew. Can be detected with high accuracy.
[0026]
A fourth aspect of the invention is characterized in that the conveyance abnormality detection condition of the conveyance abnormality detection means is set by the setting method according to the second aspect.
[0027]
The operation of the fourth aspect of the invention will be described.
[0028]
Since the registration deviation abnormality detection condition is set with high accuracy by the setting method according to claim 2, the conveyance abnormality detection means can accurately detect the registration deviation without being affected by the sensitivity of the end detection means and the mounting error. It can be detected.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
An image forming apparatus including a sheet conveying device according to a first embodiment of the present invention will be described.
(General description of the image forming apparatus)
As shown in FIG. 2, the image forming apparatus 10 includes a paper feeding unit 14 that supplies paper, a conveyance abnormality detection unit 16 to be described later, and an image forming unit that forms a predetermined image on the paper. 18, a fixing unit 20 that fixes a formed image on a sheet, a reference sensor mounting unit 22 to which reference sensors 52A and 52B, which will be described later, are mounted, a discharge tray 24 for discharging a sheet on which an image is formed, and an image This is basically composed of a purge tray 26 from which a sheet with poor formation is discharged.
[0030]
In the image forming unit 18, a charger 30, an optical scanning device 32, a developing unit 34, a transfer unit 36, and a cleaning unit 38 for removing toner are disposed around the photosensitive belt 28. Therefore, an electrostatic latent image is formed on the photosensitive belt 28 charged by the charger 30 by the laser beam from the optical scanning device 32, and a toner image is formed on the portion by the developing device 34. The toner image formed on the photoreceptor belt 28 is transferred from the photoreceptor belt 28 to the sheet by the transfer device 36, and the toner remaining on the photoreceptor belt 28 is removed by the cleaning unit 38.
[0031]
As shown in FIG. 5A, the conveyance abnormality detection unit 16 has a pair of lines arranged in a straight line at a predetermined interval in a direction orthogonal to the sheet conveyance direction of the conveyance path 12 (hereinafter referred to as the width direction). It is comprised from the edge part detection sensors 50A and 50B. The end detection sensors 50A and 50B are each constituted by a transmissive photoelectric switch including a light emitting element and a light receiving element. Therefore, each time the sheet passes the positions of the edge detection sensors 50A and 50B, the leading edge and the trailing edge of the sheet are detected based on the output signals of the edge detection sensors 50A and 50B (see FIG. 5B). Is possible.
[0032]
As shown in FIG. 6A, a pair of reference sensors 52A and 52B arranged on a straight line at a predetermined interval in the width direction of the transport path 12 are mounted on the correction reference unit 22. As shown in FIG. 3, this mounting position is the same position as the arrangement positions of the end detection sensors 50 </ b> A and 50 </ b> B in the width direction of the transport path 12.
[0033]
The reference sensors 52A and 52B are reflection type sensors that detect the amount of reflected light irradiated on the image forming surface of the paper. Therefore, the leading edge and the trailing edge of the paper are detected by the output signal (see FIG. 6B), and the leading edge and the trailing edge of black reference images 54A and 54B formed on the image forming surface described later are detected. Can do. The reference sensors 52A and 52B are mounted only during correction, which will be described later, and are positioned and fixed with high accuracy.
[0034]
Further, as shown in FIG. 4, the image forming apparatus 10 includes a control unit 40, and the output signals of the end detection sensors 50 </ b> A and 50 </ b> B and the reference detection sensors 52 </ b> A and 52 </ b> B are input and the operation unit. In response to input from 42, image formation is performed, test printing is started, and the processing state of the image forming apparatus 10 is displayed on the display 44.
[0035]
The control unit 40 calculates a time difference (shift amount) ΔT1 of the edge detection timing of the sheet based on output signals from the edge detection sensors 50A and 50B (see FIG. 5B), and based on the time difference ΔT1. It is set to detect conveyance abnormality. Specifically, when the time difference ΔT1 is not within a predetermined range, it is determined that the skew of the sheet is equal to or greater than the allowable range (conveyance abnormality) and the purge tray 26 is not formed without image formation on the sheet. It is set to display the error message on the display 44 while discharging.
[0036]
The control unit 40 also receives the output signals (see FIG. 6B) of the reference sensors 52A and 52B when the above-described conveyance abnormality detection condition is corrected by a correction method described later. . In the case of the reference sensors 52A and 52B, not only the leading and trailing edges of the paper but also black reference images 54A and 54B formed on the paper can be detected. That is, as shown in FIG. 6B, the detection signals of the reference sensors 52A and 52B fall at the leading edge of the paper, rise at the leading edge of the image, and fall at the trailing edge of the image. From these signal changes, passage times T2A and T2B from the front end of the sheet to the rear end of the image are obtained for each of the reference sensors 52A and 52B, and a time difference ΔT2 = T2A−T2B between the reference sensors 52A and 52B is obtained (FIG. 8 (B)).
[0037]
Further, the control unit 40 corrects the conveyance abnormality detection condition from the above-described time difference ΔT1 and time difference ΔT2.
[0038]
The conveyance abnormality detection in the image forming apparatus 10 configured as described above will be described with reference to the flowchart shown in FIG.
[0039]
First, when an operator inputs from the operation unit 42, a test signal is input to the control unit 40 (step 100). Based on this test signal, a drive signal is transmitted from the control unit 40 to the conveyance system of the apparatus, and the paper A is conveyed from the paper supply unit 14 to the image forming unit 18 (step 102). At the same time, a reference image creation signal (image data of the reference image) is output to the optical scanning device 32 (step 104).
[0040]
When the sheet A passes through the conveyance abnormality detection unit 16 in the conveyance path 12, the control unit 40 determines the trailing edge of the sheet A between the end detection sensors 50A and 50B based on the detection signals of the end detection sensors 50A and 50B. A time difference ΔT1 of the detection timing is calculated (step 106).
[0041]
This time difference ΔT1 detects the time difference of the detection timing due to the skew feeding of the paper A, but also includes the time difference due to the sensitivity difference between the edge detection sensors 50A and 50B and the attachment error. For example, as shown in FIG. 7A, when the end detection sensors 50A and 50B are slightly offset in the transport direction due to attachment errors, the time difference due to this offset is also included. That is, as shown by a two-dot chain line in FIG. 7A, it includes a time difference ΔT5 that is detected even when the paper A does not skew (see FIG. 7B).
[0042]
Subsequently, an image is formed when the sheet A reaches the transfer unit 20. Here, on the basis of the image data of the test image described above, the black reference images 54A and 54B on the rectangle are formed at the same timing at positions corresponding to the positions of the reference sensors 52A and 52B in the sheet width direction.
[0043]
When the sheet A on which the reference images 54A and 54B are formed reaches the correction reference unit 22, the control unit 40, as shown in FIG. 8B, based on output signals from the reference sensors 52A and 52B. Then, passage times T2A and T2B from the leading edge of the sheet to the trailing edge of the reference image are obtained, and a time difference ΔT2 = T2A−T2B is calculated therefrom (step 108).
[0044]
The passage times T2A and T2B do not depend on the mounting errors of the reference sensors 52A and 52B. That is, as shown in FIG. 8A, when the reference images 54A and 54B are formed on the paper A by the image forming unit 18, the reference images 54A and 54B have the same timing regardless of the skew state of the paper A. Formed with. That is, as shown in FIG. 8A, when the paper A is skewed, the distance from the front edge of the paper to the rear edge of the reference image varies along the transport direction. Moreover, the passage times T2A and T2B do not depend on attachment errors because the passage times from the leading edge of the paper A to the trailing edges of the reference images 54A and 54B are detected on the respective reference sensors 52A and 52B. (See FIGS. 8B and 52B). For example, even if the reference sensor 52B is offset in the transport direction (see the broken line portion in FIG. 8A), the passage time T2 does not change. The same sensitivity is selected for the reference sensors 52A and 52B. Therefore, it can be said that the time difference ΔT2 is a time difference based only on the skew feeding amount of the paper A.
[0045]
Subsequently, the control unit 40 determines whether or not the time difference ΔT1 and the time difference ΔT2 are equal (step 110). As described above, the time difference ΔT1 may include the time difference due to the skew of the paper A and the time difference due to the sensor mounting error and the sensitivity difference of the sensor. Therefore, the time difference ΔT1 is compared with the time difference ΔT2 based only on the paper skew. The presence / absence of an attachment error or the like of the end detection sensors 50A and 50B is determined.
[0046]
Therefore, when the time difference ΔT1 and the time difference ΔT2 are equal, it is determined that there is no attachment error (offset in the conveyance direction) or sensitivity difference between the end detection sensors 50A and 50B, and a message indicating that the correction process has ended is displayed on the display 44. The correction process is terminated (step 114).
[0047]
On the other hand, if the time difference ΔT1 and the time difference ΔT2 are not equal, it is determined that there is an attachment error (offset in the conveyance direction) or sensitivity difference between the end detection sensors 50A and 50B, and the abnormality detection condition is corrected (step 112). ). Specifically, (ΔT1−ΔT2) is set as a correction value, and (ΔT1−ΔT2) is added to ΔT1 when the above-described skew detection sensor time difference ΔT1 is detected in the abnormality detection control (| The abnormality detection condition is changed so that abnormality is detected based on a value obtained by adding and subtracting ΔT1−ΔT2 |. Subsequently, a correction processing end message is displayed on the display 44, and the correction processing ends (step 114). After the correction is completed, the reference sensors 52A and 52B are removed from the reference sensor mounting portion 22 of the image forming apparatus 10.
[0048]
As described above, in the present embodiment, the reference sensors 52A and 52B are accurately attached to the conveyance path 12 of the image forming apparatus 10 and the reference images 54A and 54B are formed on the sheet. It is possible to correct the abnormality detection condition with high accuracy simply by transporting the paper.
[0049]
In particular, since the reference sensors 52A and 52B are mounted on the image forming apparatus 10 as jigs, influences due to differences in sensor sensitivity, mounting errors, and the like can be removed, and accurate correction can be performed.
(Second Embodiment)
Next, a registration deviation detection setting method of the image forming apparatus according to the second embodiment of the present invention will be described. The same components as those in the first embodiment are denoted by the same components, and detailed description thereof is omitted.
[0050]
That is, only the end detection sensor 50B is disposed in the conveyance abnormality detection unit 16 of the image forming apparatus 10 (see FIG. 9A), and only the reference sensor 52B is disposed in the reference sensor mounting portion 22 (see FIG. 9A). 10A).
[0051]
The control unit 40 detects an elapsed time T3 between an input timing of a reference signal, which will be described later, and a trailing edge passage timing of the sheet A based on an output signal of the edge detection sensor 50B. A detection program for detecting a registration deviation based on the difference from the elapsed time Tp is stored.
[0052]
In addition, the control unit 40 stores a detection condition setting program for setting the registration deviation detection condition of this detection program, and the setting is automatically made based on the input signals from the end detection sensor 50B and the reference sensor 52B. Done.
[0053]
A method for setting the registration deviation detection condition of the image forming apparatus configured as described above will be described in detail with reference to the flowchart shown in FIG.
[0054]
First, when an operator inputs from the operation unit 42, a test signal is input to the control unit 40 (step 200). Based on this test signal, a drive signal is transmitted from the control unit 40 to the conveyance system of the apparatus, and the paper A is conveyed from the paper supply unit 14 toward the image forming unit 18 (step 202). At the same time, a reference image creation signal (image data of the reference image) is output to the optical scanning device 32 (step 204).
[0055]
When the sheet A passes through the conveyance abnormality detection unit 16 in the conveyance path 12, the control unit 40 detects the edge from the input of the reference signal (in this embodiment, the test signal) based on the detection signal of the edge detection sensor 50B. The elapsed time T3 (see FIG. 9B) of the trailing edge detection timing of the sensor 50B is calculated (step 206).
[0056]
Subsequently, when the sheet A reaches the transfer unit 20, an image is formed. Here, a rectangular black reference image 54B is formed at a predetermined timing on the position of the sheet A corresponding to the position of the reference sensor 52B in the width direction of the sheet A based on the image data of the test image described above ( (See FIG. 10A).
[0057]
Furthermore, when the sheet A on which the reference image 54B is formed reaches the correction reference unit 22, the control unit 40 from the leading edge of the sheet A to the rear end of the reference image 54B based on the output signal of the edge detection sensor 52B. Is obtained (see FIG. 10B) (step 208).
[0058]
Next, the control unit 40 reads a set passage time Tr that is theoretically obtained from the end of the paper until the rear end of the reference image 54B passes the reference sensor 52B (step 210).
[0059]
Subsequently, it is determined whether or not the passage time T4 matches the set passage time Tr (step 212).
[0060]
This passage time T4 does not depend on the mounting error or sensitivity difference of the reference sensor 52B. That is, as shown in FIG. 10A, it depends purely on the position of the reference image 54B on the paper A. Therefore, the presence or absence of registration deviation can be determined by comparing with the set transit time Tr.
[0061]
That is, when the passage time T4 matches the set passage time Tr (T4 = Tr), there is no registration deviation. In this case, the elapsed time T3 is set to the set elapsed time Tp (step 214). Since there is no registration deviation at the elapsed time T3, the elapsed time T3 is set as a reference value for registration deviation detection.
[0062]
Further, in step 212, when the passage time T4 and the set passage time Tr are different, that is, when a registration deviation occurs, the elapsed time T3 is equivalent to the time corresponding to the registration deviation amount (Tr-T4). The subtracted value is set as the set elapsed time Tp (step 216).
[0063]
As described above, when the set elapsed time Tp (registration deviation detection condition) is set, a message indicating the end of setting is displayed on the display 44 and the setting is ended (step 218).
[0064]
As described above, in the present embodiment, only the reference sensor 52B is accurately attached to the conveyance path 12 of the image forming apparatus 10 and the reference image 54B is formed on the sheet. By simply carrying, it is possible to accurately set a condition for detecting a conveyance abnormality (registration deviation).
[0065]
In particular, since the reference sensor 52B is mounted on the image forming apparatus 10 as a jig, it is possible to eliminate the influence due to the difference in sensitivity of the sensor, the mounting error, and the like, and correct with high accuracy.
[0066]
In addition, although 1st Embodiment and 2nd Embodiment were demonstrated as another structure here, it can also be comprised integrally. That is, with the configuration of the first embodiment, it is possible to correct skew detection conditions and set registration deviation detection conditions.
[0067]
【The invention's effect】
According to the present invention, it is possible to correct or set the abnormality detection condition of the conveyance abnormality detection unit easily and accurately by reliably removing the influence of the attachment error of the end detection unit and the sensitivity difference.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a skew detection condition correction method according to a first embodiment of the present invention.
FIG. 2 is a schematic explanatory diagram of an image forming apparatus according to the first embodiment of the present invention.
FIG. 3 is an explanatory plan view showing the positional relationship between the end detection sensor and the reference sensor according to the first embodiment of the present invention.
FIG. 4 is a schematic configuration diagram of an image forming apparatus according to the first embodiment of the present invention. .
5A is an explanatory plan view showing a positional relationship between a sheet and an edge detection sensor in a conveyance path, and FIG. 5B is a timing showing a waveform of an output signal of each edge detection sensor when the sheet passes. It is a chart.
6A is an explanatory plan view showing a positional relationship between a sheet and a reference sensor in a conveyance path, and FIG. 6B is a timing chart showing waveforms of output signals of the respective reference sensors when the sheet passes.
7A is an explanatory plan view showing the positional relationship between the sheet and the edge detection sensor in the conveyance path, and FIG. 7B is a timing showing the waveform of the output signal of each edge detection sensor when the sheet passes. It is a chart.
8A is an explanatory plan view showing a positional relationship between a sheet and a reference sensor in a conveyance path, and FIG. 8B is a timing chart showing waveforms of output signals of the respective reference sensors when the sheet passes.
9A is an explanatory plan view showing a positional relationship between a sheet and an edge detection sensor in a conveyance path according to a second embodiment of the present invention, and FIG. 9B is an edge detection sensor when the sheet passes. 6 is a timing chart showing waveforms of the output signal and the test signal.
10A is an explanatory plan view showing a positional relationship between a sheet and a reference sensor in a conveyance path according to a second embodiment of the present invention, and FIG. 10B is an output signal of the reference sensor when the sheet passes. It is a timing chart which shows a waveform.
FIG. 11 is a flowchart showing a registration deviation detection condition setting method according to the second embodiment of the present invention.
[Explanation of symbols]
10. Image forming apparatus
12 ... Conveying path
18. Image forming unit (image forming means)
40. Control unit (correction means)
50A, 50B ... end detection sensor (end detection means)
52A, 52B ... Reference sensor (end detection means)
54A, 54B ... Reference image (measuring means)

Claims (4)

In the image forming apparatus, the amount of deviation of the edge detection timing of the sheet detected by a plurality of edge detection means arranged in a straight line at a predetermined interval in the width direction orthogonal to the sheet conveyance direction on the conveyance path. A correction method for a conveyance abnormality detecting means for detecting abnormality in paper conveyance based on
A first step of detecting an end portion of the paper conveyed on the conveyance path by the plurality of edge detection means;
A second step of forming a plurality of the same reference images at the same timing by the image forming means at a position on the paper corresponding to the position where the end detection means is disposed in the width direction of the transport path;
A plurality of measuring means are mounted on the conveyance path downstream of the image forming means at a position corresponding to the position where the edge detecting means is disposed in the width direction, and the reference image is formed from the edge of the paper. A third step in which each measuring means measures the passing time until
The detection timing deviation amount by the plurality of end detection means and the passage time deviation amount by the plurality of measurement means are obtained, and the detection timing deviation amount and the passage time deviation amount are calculated as the detection timing deviation amount. A fourth step of changing the abnormality detection condition of the conveyance abnormality detection means so as to detect a conveyance abnormality of the sheet based on a value obtained by adding or subtracting the difference between
A correction method for a conveyance abnormality detection unit of an image forming apparatus. In the image forming apparatus, a method for setting a conveyance abnormality detection unit that detects a registration deviation based on an elapsed time from a reference timing to a sheet edge detection timing detected by an edge detection unit disposed on the conveyance path. There,
A first step of detecting an elapsed time from the reference timing to detection of an end portion of a sheet conveyed on the conveyance path by the edge detection unit;
A second step in which an image forming unit forms a reference image at a predetermined timing at a position on the sheet corresponding to a position where the end detection unit is disposed in the width direction of the conveyance path;
A measuring unit is mounted at a position corresponding to the position where the end detection unit is disposed in the width direction in the conveyance path on the downstream side of the image forming unit, and passes from the end of the sheet to the reference image. A third step in which the measuring means measures the passing time to
A fourth step of obtaining a difference between the passage time and the theoretical passage time, and setting an abnormality detection condition of the conveyance abnormality detection means so as to detect a registration deviation based on a time obtained by adding or subtracting the difference to the elapsed time; ,
A method for setting a conveyance abnormality detection unit of the image forming apparatus. The image forming apparatus according to claim 1, wherein a conveyance abnormality detection condition of the conveyance abnormality detection unit is corrected by the correction method according to claim 1. The image forming apparatus according to claim 2, wherein a conveyance abnormality detection condition of the conveyance abnormality detection unit is set by the setting method according to claim 2.

Images