JP6977478B2 - Image processing device, detection method of recording medium in image processing device, and control program - Google Patents

Description

The present disclosure relates to an image processing apparatus, and more specifically to paper detection in the image processing apparatus.

Conventionally, it has been known that an image processing device such as an image forming apparatus performs correction processing by recognizing an end portion, a vertex, a straight line portion, a character area, or the like of an image once read. In this case, in order to reduce the burden of image processing after scanning, a technique has been developed for optimizing the reading area and reducing the burden of image processing by detecting the conveyed state of the paper before scanning the image.

For example, Japanese Patent Application Laid-Open No. 6-92512 (Patent Document 1) discloses an image processing apparatus that "corrects misalignment and skew of paper positioning in an automatic document feeder with high accuracy and without reducing productivity". (See [Solution] in [Summary]). Further, Japanese Patent Application Laid-Open No. 11-298712 (Patent Document 2) discloses "an image reading device having extremely little tilt or deviation of an image obtained by image reading".

Japanese Unexamined Patent Publication No. 6-92512 Japanese Unexamined Patent Publication No. 11-298712

However, in the above-mentioned conventional technique, there is a problem that the detection result of the offset in the main scanning direction of the paper becomes unstable. Therefore, there is a need for a technique for more accurately detecting the conveyed state of paper.

The present disclosure has been made to solve the above-mentioned problems, and an object in a certain aspect is to provide an image processing apparatus for more accurately detecting a conveyed state of an image.

According to a certain aspect, an image processing device for reading an image on a recording medium is provided. The image forming apparatus detects the transport path on which the recording medium is transported, the controller, the front end sensor that detects the front end of the recording medium in the transport direction in the transport path, and the side edge of the recording medium in the main scanning direction that intersects the transport direction. It is equipped with a side end sensor. The controller detects the offset amount in the main scanning direction of the recording medium based on the output value from the side end sensor at a predetermined detection timing after the timing when the front end sensor detects the front end of the recording medium.

Preferably, the front end sensor further detects the tilt of the front end of the recording medium with respect to the main scanning direction. The controller estimates the tilt of the recording medium with respect to the main scanning direction based on the rate of change of the output value of the side end sensor as the recording medium is conveyed, and determines the estimated tilt and the tilt detected by the front end sensor. Based on the output value from the side end sensor at the timing when the above relationship is satisfied, the offset amount in the main scanning direction of the recording medium is detected.

Preferably, the predetermined relationship is that the detected slope and the estimated slope match.

Preferably, the detection timing is the timing at which the detected tilt and the estimated tilt first match after the front end sensor detects the front end.

According to other aspects, an image processing device for reading an image on a recording medium is provided. The image processing device mainly includes a transport path in which the recording medium is transported, a controller, and a rear end tilt sensor that detects the tilt of the rear end of the recording medium in the transport direction in the transport path with respect to the main scanning direction intersecting the transport direction. It includes a side edge sensor that detects the side edge of the recording medium in the scanning direction. The controller estimates the tilt of the recording medium with respect to the main scanning direction based on the rate of change of the output value of the side end sensor as the recording medium is conveyed, and the estimated tilt and the tilt detected by the rear end tilt sensor. At the same timing, the amount of deviation in the main scanning direction of the recording medium is detected based on the output value from the side end sensor.

According to other aspects, an image processing device for reading an image on a recording medium is provided. The image processing device includes a transport path on which the recording medium is transported, a controller, a first tilt sensor that detects the tilt of the front end of the recording medium with respect to the main scanning direction intersecting the transport direction in the transport path, and a rear end of the recording medium. The second tilt sensor for detecting the tilt with respect to the main scanning direction and the side edge sensor for detecting the side edge of the recording medium in the main scanning direction are provided. The controller estimates the tilt of the recording medium with respect to the main scanning direction based on the rate of change of the output value of the side end sensor as the recording medium is conveyed, and the tilt detected by the first tilt sensor and the second tilt sensor detect it. The amount of deviation in the main scanning direction of the recording medium is detected based on the output value from the side end sensor at the timing corresponding to at least one of the tilts.

Preferably, the controller calculates the first and second estimates of the tilt of the recording medium based on the rate of change of the recording medium at the side edge position detected by the side edge sensor. The tilt detected by the first tilt sensor matches the first estimated value, the tilt detected by the second tilt sensor matches the second estimated value, and the tilt detected by the first tilt sensor and the second tilt sensor. When the inclination does not match the inclination detected by, the offset amount in the main scanning direction of the recording medium is detected based on the output value from the side end sensor with respect to the side end used for calculating the second estimated value.

Preferably, the controller has the estimated tilt as either the tilt detected by the first tilt sensor or the tilt detected by the second tilt sensor, depending on the rate of change of the recording medium of the side end sensor. Decide whether to detect the offset amount when they match.

Preferably, the controller is offset when the estimated tilt of the recording medium with respect to the main scanning direction does not match both the tilt detected by the first tilt sensor and the tilt detected by the second tilt sensor. Does not detect.

Preferably, the image processing apparatus further comprises an interface for accepting input of information for setting the position of the detection target of the offset amount on the recording medium. When information is input via the interface, the controller detects the amount of deviation in the main scanning direction of the recording medium based on the output value of the side end sensor with respect to the position of the detection target.

Preferably, the information is information about the shape of the recording medium.
Preferably, the information is information about the thickness of the recording medium.

Preferably, the front end sensor detects the front end of the recording medium as a digital value, and the side end sensor detects the side end of the recording medium as an analog value.

Preferably, the image processing apparatus includes a reading unit for reading an image on the recording medium, and the controller sets a region for the reading unit to read the image on the recording medium based on the offset amount.

Preferably, the controller rotates the scanned image around a point in the center of the area on a line along the main scanning direction through the side edge detected by the side edge sensor due to the offset amount. , Correct the tilt of the image.

According to another aspect, a method for detecting a recording medium in an image processing apparatus for reading an image on the recording medium is provided. The image processing apparatus includes a transport path through which the recording medium is transported. The detection method is predetermined after a step of detecting the front end of the recording medium in the transport direction in the transport path, a step of detecting the side edge of the recording medium in the main scanning direction intersecting the transport direction, and a step of detecting the front end of the recording medium. This includes a step of detecting a biased amount in the main scanning direction of the recording medium based on the detection result in the step of detecting the side edge at the timing of.

According to still another aspect, a control program is provided that causes a computer to execute a method for detecting a recording medium in an image processing device that reads an image on the recording medium. The image processing apparatus includes a transport path through which the recording medium is transported. The control program tells the computer a step of detecting the front end of the recording medium in the transport direction in the transport path, a step of detecting the side edge of the recording medium in the main scanning direction intersecting the transport direction, and a step of detecting the front end of the recording medium. Based on the detection result in the step of detecting the side edge at a predetermined timing later, the step of detecting the offset amount in the main scanning direction of the recording medium is executed.

In a certain aspect, the image processing apparatus can more accurately detect the conveyed state of the paper.

The above and other objectives, features, aspects and advantages will be apparent from the following detailed description understood in connection with the accompanying drawings.

It is a figure which shows the outline of the image forming apparatus. It is a figure which shows the hardware composition of the image forming apparatus. It is sectional drawing of the ADF unit provided with the image forming apparatus. It is a figure which shows the outline of the paper detection in an image reading process. It is a figure which shows the output value of the front edge sensor and the side edge sensor in the paper detection. It is a figure which shows the setting of the reading area in the image reading process. It is a figure which shows the correction process of the scanned image in the image scanning process. It is a flowchart which shows the procedure of an image reading process. It is a figure which shows the outline of the image reading process in 2nd Embodiment. It is a figure which shows the output value of the front edge sensor and the side edge sensor in the paper detection. It is a figure which shows an example of the detection timing and the detection place which detects the offset amount. It is a figure which shows the detection timing which detects the offset amount, and other examples of the detection location. It is a figure which shows the outline of the image reading process in 3rd Embodiment. It is a figure which shows an example of the method of determining the offset detection timing which concerns on 3rd Embodiment. It is a figure which shows the other example of the method of determining the offset detection timing which concerns on 3rd Embodiment. It is a figure which shows the outline of the image reading process in 4th Embodiment.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In the following description, the same parts and components are designated by the same reference numerals. Their names and functions are the same. Therefore, the detailed description of these will not be repeated. In addition, each embodiment and each modification described below may be selectively combined as appropriate.

<First Embodiment>
[1. Configuration of image forming apparatus 100]
FIG. 1 is a diagram showing an outline of an image forming apparatus 100 as an example of an image processing apparatus. As shown in FIG. 1, the image forming apparatus 100 is configured as a so-called MFP (Multi Function Peripheral), and includes a controller 101, an image forming unit 20, a paper feeding unit 30, a scanner unit 40, and an ADF (Auto Document Feeder). : Automatic document transfer device) A unit 50 and an operation panel 60 are provided. The controller 101, the image forming unit 20, and the feeding unit 30 are located in the central portion of the image forming apparatus 100. The scanner unit 40 and the ADF unit 50 are located on the upper part of the image forming apparatus 100. The operation panel 60 is located on the upper front surface of the image forming apparatus.

FIG. 2 is a diagram showing a hardware configuration of the image forming apparatus 100. As shown in FIG. 2, the controller 101 includes a CPU (Central Processing Unit) 11, a ROM (Read Only Memory) 12, a RAM (Random Access Memory) 13, a communication I / F (Interface) unit 14, and an image. A data storage unit 15 and a paper size storage unit 16 are included. Each of the CPU 11, ROM 12, RAM 13, communication I / F unit 14, image data storage unit 15, and paper size storage unit 16 is connected so as to enable data linkage with each other.

The CPU 11 controls the operation of the entire image forming apparatus 100. The ROM 12 stores a control program executed by the CPU 11. The RAM 13 is a working memory of the CPU 11. The communication I / F unit 14 transmits / receives various information to / from an external device (not shown) via a network or the like. The image data storage unit 15 stores image data and the like read by the scanner unit 40. The paper size storage unit 16 stores the paper size measured by the ADF unit 50 and the paper size set through the operation panel 60.

Here, the control program executed by the CPU 11 may be provided by being incorporated into a part of an arbitrary program as a module, not as a single program. In this case, the control process according to the present embodiment is realized in cooperation with an arbitrary program. Further, some or all of the functions provided by the control program may be realized by dedicated hardware. Further, the image forming apparatus 100 may be configured in the form of a so-called cloud service in which at least one server executes a part of the processing of the control program.

The image forming unit 20 is roughly composed of a toner image forming unit, a fixing device, and the like. The image forming unit 20 forms an image on paper by, for example, an electrophotographic method. The image forming unit 20 is configured to be capable of forming a color image on paper by synthesizing four-color images by a so-called tandem method.

The toner image forming portion is between the photoconductor provided for each color of C (cyan), M (magenta), Y (yellow), and K (black) and the intermediate in which the toner image is transferred (primary transfer) from the photoconductor. It is composed of a transfer belt and a transfer unit that transfers an image from an intermediate transfer belt to paper (secondary transfer).

The fixing device has a heating roller and a pressure roller. The fixing device conveys the paper on which the toner image is formed between the heating roller and the pressure roller while sandwiching the paper, and heats and pressurizes the paper. As a result, the fixing device melts the toner adhering to the paper and fixes it on the paper, and forms an image on the paper.

The paper feed unit 30 is composed of a paper feed roller, a transport roller, a motor for driving them, and the like. The paper feed unit 30 feeds paper from the paper feed cassette and conveys it inside the housing of the image forming apparatus 100. The paper feeding unit 30 ejects the paper on which the image is formed from the image forming apparatus to a paper ejection tray or the like. The scanner unit 40 reads the image of the paper and creates the image data of the paper.

The ADF unit 50 sends paper (an example of a recording medium) one by one to the scanner unit 40. The ADF unit 50 includes a paper transport motor 51, a back surface reading means 52 provided when double-sided simultaneous reading is performed during paper transport, a paper size detection sensor 53, an empty sensor 160, a front end sensor 57, and a side end sensor 58. The paper transport motor 51 operates under the control of the CPU 11. The details of the paper reading process by the front end sensor 57 and the side end sensor 58 will be described later.

The operation panel 60 displays various information and accepts various operations. The operation panel 60 includes a start button 61 for starting various jobs such as a read job and a copy job.

FIG. 3 is a cross-sectional view of the ADF unit 50 included in the image forming apparatus 100. The internal structure of the ADF unit 50 will be described with reference to FIG.

The ADF unit 50 is a sheet-through type automatic paper feeder, and conveys paper to reading positions 114 and 115, which will be described later, for reading paper. The ADF unit 50 has a paper feed tray 121 for loading paper before transfer and a paper discharge tray 109 for discharging paper after transfer, and the paper feed tray 121 and the output tray 109 A paper transport path 42 is configured between them.

A pick roller 102 and a pair of sorting rollers 103 are provided at a boundary position between the paper feed tray 121 and the transport path 42. The bundle of paper loaded on the paper feed tray 121 is fed by the pick roller 102, separated one by one by the pair of sorting rollers 103, and sent out to the transport path 42.

In the following description, the transport direction of the transport path 42, that is, the paper feed tray 121 side in the direction from the paper feed tray 121 to the paper output tray 109 is referred to as "upstream side in the transport direction", and the paper output tray 109 side is "conveyed". Also described as "downstream side in the direction". Further, the upstream side of the transport path 42 is also described as "front" and the downstream side is also described as "rear", and for the paper transported in the transport path 42, the end on the transport path 42 side is referred to as the "front end" and the downstream end. The part shall be described as "rear end".

The transport path 42 is provided with a pair of resist rollers 104 that sandwich the transport path 42 along the transport direction. The paper fed to the resist roller 104 on the transport path 42 by the sorting roller 103 is skew-corrected by the resist roller 104. Then, the skew-corrected paper is conveyed to the reading position 114.

A pair of reading rollers 105 and 106 are provided on the upstream side and the downstream side of the transfer path 42 at the positions corresponding to the reading positions 114, respectively. Due to the rotation of these roller pairs, the conveyed paper passes through the reading position 114 and is conveyed downstream. As a result, the side of the paper facing the scanner unit 40 is read by the scanner unit 40. In the following description, the side of the conveyed paper facing the scanner unit 40 is also referred to as a “front side”, and the opposite side thereof is also referred to as a “back side”.

The reading unit 22 is arranged on the downstream side of the conveying path 42 with respect to the reading roller 106 with the image pickup unit facing the back surface of the conveyed paper. A pair of reading rollers 107 are provided on the downstream side of the reading unit 22. Due to the rotation of the reading rollers 106 and 107, the conveyed paper passes through the reading unit 22 and is conveyed to the downstream side. As a result, the back surface of the paper passing through the reading position 115 is read by the reading unit 22.

A paper ejection roller 108 is provided at a boundary position between the transport path 42 and the paper ejection tray 109. Due to the rotation of the paper ejection roller 108, the paper that has been conveyed and the back surface of which has been read by the reading unit 22 is ejected to the paper ejection tray 109.

The pre-reading sensor 113 is arranged near the upstream side of the reading position 114 of the transport path 42, the resist sensor 112 is arranged near the upstream side of the resist roller 104, and the separation sensor 111 is arranged near the downstream side of the sorting roller 103. There is. These sensors detect the presence or absence of paper at that position.

The front end sensor 57 and the side end sensor 58 are arranged upstream of the pre-reading sensor 113 and downstream of the resist sensor 112 in the transport path 42. These sensors detect the front and side edges of the paper at that location.

[2. Image reading process]
The image reading process will be described with reference to FIGS. 4 to 7. FIG. 4 is a diagram showing an outline of paper detection in the image reading process. FIG. 5 is a diagram showing output values of the front edge sensor 57 and the side edge sensor 58 in paper detection. FIG. 6 is a diagram showing a setting of a reading area in the image reading process. FIG. 7 is a diagram showing a correction process of a scanned image in the image scanning process.

As shown in FIG. 4, a front end sensor 57 and a side end sensor 58 are arranged in the transport path 42 so as to detect the paper S to be transported. When the paper S is conveyed in the conveying path 42, for example, at the timing of t = T1, the front end sensor 57 detects the front end of the conveyed paper S and outputs a detection signal to the controller 101. The front end sensor 57 can be composed of, for example, a transmissive type or a reflective type photo sensor that outputs the front end detection of the paper S by a digital signal composed of “0” and “1”.

On the other hand, the side edge sensor 58 detects the side edge of the conveyed paper S and outputs a detection signal to the controller 101. The side end sensor 58 can be configured by, for example, a line sensor in which a plurality of photo sensor elements are arranged in the main scanning direction of the transport path 42. In this case, the sensor element that has detected the side edge of the paper S outputs an analog signal to the controller 101.

After that, at the timing of t = T2 when the paper S is further conveyed, the controller 101 detects the offset amount of the paper S based on the output value from the side end sensor 58.

FIG. 5 shows the output values of the front edge sensor 57 and the side edge sensor 58 in the paper detection. In FIG. 5, the front edge sensor 57 and the side edge sensor 58 indicate that the front edge and the side edge of the paper are detected when the value is ON, and the front edge and the side edge of the paper are not detected when the value is OFF. ing.

As shown in FIG. 5, immediately after the timing when the front end sensor 57 detects the tip of the paper S, the output value of the side end sensor 58 drops once. After that, it rises again and becomes a stable value. It is considered that the output value of the side edge sensor 58 becomes unstable in this way because the front edge of the paper S may be damaged or curled while being conveyed in the transfer path 42.

Therefore, the controller 101 according to the present embodiment is an output value from the side edge sensor 58 at a predetermined timing (t = T2 in FIG. 4) after the timing when the front edge of the paper S is detected (t = T1 in FIG. 4). Based on the above, the amount of offset in the main scanning direction of the paper S is detected. The predetermined timing can be predetermined, for example, from the size of the paper S and the transport speed of the paper S. By doing so, it is possible to detect the offset amount of the paper S at the timing when the output of the side edge sensor 58 is stabilized, so that it is possible to detect the offset amount of the paper more accurately. It becomes.

After that, as shown in FIG. 6, the controller 101 sets the reading area of the paper S at the reading positions 114 and 115 based on the offset amount detected by the above processing. In the example shown in FIG. 6, the image of the paper S is read by securing a width of 4.4 mm in the main scanning direction based on the detected offset amount.

After that, as shown in FIG. 7, the controller 101 displays the read image centered on a point on the line in the main scanning direction passing through the offset detection point and at the center in the main scanning direction. The tilt of the image is corrected by rotating the image. By doing so, the image is corrected based on the portion where the offset of the paper is detected, so that the accuracy of the image correction is improved.

[3. Processing procedure]
The procedure of the image reading process according to the first embodiment will be described with reference to FIG. FIG. 8 is a flowchart showing the procedure of the image reading process. This process is realized, for example, by the CPU of the controller 101 executing a given program.

In step S810, the controller 101 receives the detection signal from the front end sensor 57 that has detected the front end of the paper S.

In step S820, the controller 101 determines whether or not a predetermined timing has arrived. When a predetermined timing arrives (YES in step S820), the controller 101 switches the control to step S830. If not (NO in step S820), the controller 101 performs step S820 again.

In step S830, the controller 101 detects the offset amount of the paper S based on the output value from the side edge sensor 58.

In step S840, the controller 101 sets the image reading area of the paper S based on the detected offset amount, and performs the image reading process.

In step S850, the controller 101 performs correction processing on the image read by the image reading process based on the detected offset amount. The controller 101 ends the process.

[4. Brief Summary]
As described above, in the first embodiment, the controller 101 uses the paper S based on the output value from the side end sensor 58 at a predetermined timing after the timing when the front end sensor 57 detects the front end of the paper S. Detects the amount of offset in the main scanning direction.

With the above configuration, the controller 101 detects the offset of the paper not to the front end side having a high possibility of damage in transportation but to the side end portion of the rear end side having a low possibility of damage. It is possible to accurately detect the offset of the paper.

<Second embodiment>
[1. Overview]
Hereinafter, the second embodiment will be described. In the second embodiment, the controller 201 included in the image forming apparatus 200 detects the offset amount based on the inclination of the front edge of the paper S with respect to the main scanning direction and the rate of change of the output value of the side edge sensor 58. It differs from the first embodiment in that it determines the arrival of the detection timing. In this embodiment, the same configuration as that of the image forming apparatus 100 according to the above-described embodiment is designated by the same reference numeral as that of the image forming apparatus 100. Therefore, those explanations will not be repeated.

[2. detail]
The image reading process according to the second embodiment will be described with reference to FIGS. 9 to 12. FIG. 9 is a diagram showing an outline of the image reading process according to the second embodiment. FIG. 10 is a diagram showing output values of the front edge sensor 157 and the side edge sensor 58 in paper detection. FIG. 11 is a diagram showing an example of a detection timing and a detection location for detecting a biased amount. FIG. 12 is a diagram showing another example of the detection timing and the detection location for detecting the offset amount.

As shown in FIG. 9, the front end sensor 157 in the second embodiment includes a first front end sensor 157a and a second front end sensor 157b arranged at intervals in the main scanning direction. The front end sensor 157 detects the front end of the paper S and also detects the inclination of the front end of the paper S with respect to the main scanning direction.

In the example shown in the minute diagram (A) of FIG. 9, the second front end sensor 157b detects the front end of the paper S conveyed in the transport path 42. When the second front end sensor 157b detects the front end of the paper S, the second front end sensor 157b outputs a detection signal to the controller 201.

As shown in the minute diagram (B) of FIG. 9, when the paper S is further conveyed, both the first front end sensor 157a and the second front end sensor 157b detect the front end of the paper S. The front end sensor 157 is the time from when the second front end sensor 157b detects the front end of the paper S until the first front end sensor 157a detects the front end of the paper S, the first front end sensor 157a and the second. The inclination of the front end of the paper S with respect to the main scanning direction is detected based on the distance from the front end sensor 157b and the transport speed of the paper S. The front end sensor 157 outputs the detected inclination of the paper S to the controller 201.

As shown in the minute diagram (C) of FIG. 9, when the paper S is further conveyed, the side edge sensor 58 detects the side edge (between XY) on the front end side of the paper S. The side edge sensor 58 outputs a detection signal for detecting the side edge of the paper S to the controller 201. The controller 201 estimates the inclination of the paper S with respect to the main scanning direction from the rate of change of the output value of the side edge sensor 58 in the transport direction of the paper S.

As shown in the minute diagram (D) of FIG. 9, when the paper S is further conveyed, the side end sensor 58 detects the side end (between YZ) on the rear end side of the paper S. The controller 201 estimates the inclination of the paper S with respect to the main scanning direction from the rate of change of the output value of the second sensor in the transport direction of the paper S. In the example shown in FIG. 9, since the side end portion on the front end side of the paper S is cut, the controller 201 has different estimated values of the paper S between the side edge XY and the side edge YZ of the paper S. It will be.

With reference to FIG. 10, the output values of the front end sensor 157 and the side end sensor 58 in the above process will be described. In FIG. 10, the front edge sensor 157 and the side edge sensor 58 indicate that the front edge and the side edge of the paper are detected when the value is ON, and the front edge and the side edge of the paper are not detected when the value is OFF. ing.

In FIG. 10, the timings corresponding to the segments (A) to (D) of FIG. 9 are shown on the horizontal axis as t = a to d, respectively. That is, at the timing of t = a and the timing of t = b, the side edge sensor 58 does not detect the side edge of the paper S. On the other hand, at the timing of t = c and the timing of t = d, the side edge sensor 58 detects the side edge of the paper S.

In FIG. 10, the rate of change (inclination) of the output value of the side end sensor 58 at the timing of t = c and the timing of t = d are different. This is because, as shown in FIG. 9, since the end portion of the paper S on the front end side is cut, the inclination of the side edge of the paper S with respect to the transport direction differs between the side edge XY and the side edge YZ. Is. Here, the inclination of the paper S with respect to the main scanning direction estimated from the rate of change of the output value of the side edge sensor 58 between the side edge XY is set as the first estimated value, and the output value of the side edge sensor 58 between the side edge YZ is taken as the first estimated value. The following description will be continued with the inclination of the paper S estimated from the rate of change with respect to the main scanning direction as the second estimated value.

As shown in FIG. 11, with respect to the paper S, the front end sensor 157 detects the inclination of the front end of the paper S with respect to the main scanning direction (hereinafter, referred to as an inclination detection value). As described above, the controller 201 estimates the inclination of the paper S with respect to the main scanning direction as the first estimated value based on the rate of change of the output value of the side edge sensor 58 with respect to the distance between the side edges XY of the paper S. Further, the controller 201 estimates the inclination of the paper S with respect to the main scanning direction as the second estimated value based on the rate of change of the output value of the side edge sensor 58 with respect to the space between the side edges YZ of the paper S.

The controller 201 sets the timing at which the tilt detection value detected by the front end sensor 157 and the tilt estimation value estimated from the rate of change of the output value of the side end sensor 58 satisfy a predetermined relationship in the main scanning direction of the paper S. As the detection timing for detecting the offset amount of the paper S, the offset amount of the paper S is detected based on the output value from the side edge sensor 58.

Here, as a predetermined relationship, the tilt detection value detected by the front end sensor 157 and the tilt estimation value estimated from the rate of change of the output value of the side end sensor 58 can be in agreement with each other. That is, as shown in FIG. 11, the controller 201 detects the offset amount of the paper S based on the output value of the side end sensor 58 between the side end YZs corresponding to the second estimated value that matches the tilt detection value. do.

As shown in FIG. 12, the controller 201 has a tilt estimated from the tilt detected by the front edge sensor 157 and the rate of change of the output value of the side edge sensor 58 after the front edge sensor 157 detects the front edge of the paper S. The offset amount of the paper S may be detected by setting the timing at which and is first matched as the detection timing. By doing so, it is possible to determine the offset detection location at an earlier stage, and it is possible to smoothly perform the subsequent processing.

[3. Brief Summary]
As described above, in the second embodiment, the controller 201 has a predetermined tilt detection value detected by the front end sensor 157 and a tilt estimation value estimated from the rate of change of the output value of the side end sensor 58. When the relationship is satisfied, it is determined that the detection timing for detecting the offset amount in the main scanning direction of the paper S has arrived, and the offset amount of the paper S is detected based on the output value from the side edge sensor 58. ..

With the above configuration, the controller 201 can determine an appropriate timing according to the shape of the paper, and the accuracy of the offset amount detection is improved.

<Third embodiment>
[1. Overview]
Hereinafter, the third embodiment will be described. The third embodiment differs from the first embodiment in that the image forming apparatus 300 includes a rear end tilt sensor 59 that detects a tilt of the rear edge of the paper with respect to the main scanning direction. The image forming apparatus according to the present embodiment is realized by the same configuration as the hardware configuration included in the image forming apparatus 100 according to the above-described embodiment. Therefore, those explanations will not be repeated.

[2. detail]
The image reading process according to the third embodiment will be described with reference to FIGS. 13 to 15. FIG. 13 is a diagram showing an outline of the image reading process according to the third embodiment. FIG. 14 is a diagram showing an example of a method for determining the offset detection timing according to the third embodiment. FIG. 15 is a diagram showing another example of the method of determining the offset detection timing according to the third embodiment.

As shown in FIG. 13, the image forming apparatus 300 according to the third embodiment includes a controller 301, a front end sensor 157, a side end sensor 58, and a rear end tilt sensor 59. The rear end tilt sensor 59 includes a first rear end tilt sensor 59a and a second rear end tilt sensor 59b.

In the example shown in the minute diagram (A) of FIG. 13, the tip of the paper S in the transport direction reaches the front end sensor 157. The front end sensor 157 detects the front end of the paper S, detects the inclination of the front end of the paper S with respect to the main scanning direction (hereinafter, also referred to as the front end inclination), and outputs the tilt to the controller 301.

As shown in the segment (B) of FIG. 13, when the paper S is further conveyed, the side edge sensor 58 detects the side edge of the paper and outputs it to the controller 301. The controller 301 estimates the inclination of the paper with respect to the main scanning direction from the rate of change of the output value of the side edge sensor 58 in the paper transport direction.

As shown in the segment (C) of FIG. 13, when the paper S is further conveyed, the rear end tilt sensor 59 detects the tilt of the rear end of the paper S with respect to the main scanning direction (hereinafter, also referred to as the rear end tilt). do. The controller 301 compares at least one of the front end tilt detected by the front end sensor 157 and the rear end tilt detected by the rear end tilt sensor 59 with the tilt estimated from the rate of change of the output value of the side end sensor 58. Then, the timing for detecting the offset amount of the paper S is determined.

A method of determining the offset detection timing according to the third embodiment will be described with reference to FIG. As described above, in the third embodiment, the front edge tilt and the rear edge tilt of the paper S are detected. In the example shown in FIG. 14, the controller 301 calculates the first estimated value as the inclination of the paper S from the rate of change of the output value of the side end sensor 58 between the side ends XY of the paper S. Then, the second estimated value is calculated as the inclination of the paper S from the rate of change of the output value of the side end sensor 58 between the side ends YZ of the paper S.

The controller 301 compares the front end tilt detected by the front end sensor 157 with the first estimated value. Then, the rear end inclination detected by the rear end inclination sensor 59 is compared with the second estimated value. Then, the controller 301 determines the timing at which the detected inclination and the estimated value match as the detection timing of the offset amount of the paper S, and the offset amount of the paper S is based on the output value from the side edge sensor 58. Is detected.

In the example shown in FIG. 15, the controller 301 estimates two different inclinations from the rate of change of the output value of the side edge sensor 58, and the first estimated value and the first estimated value estimated from the output value on the front end side of the paper. The inclination matches, and the second estimated value estimated from the output value on the rear end side of the recording medium and the second inclination match. In this case, the controller 301 determines the amount of paper offset based on the output value from the side edge sensor detected by the second sensor at the timing when the second estimated value and the second inclination match. By doing so, it is possible to determine the offset detection timing based on the rear end side tilt with less damage to the paper, and the accuracy of the offset detection of the paper S is improved.

Preferably, the controller 301 detects the inclination estimated from the rate of change of the output value of the side edge sensor 58 by the front edge sensor 157 according to the rate of change of the output value of the side edge sensor 58 as the paper is conveyed. It is determined whether the offset amount is detected when the tilt coincides with the tilt detected by the rear end tilt sensor 59. By doing so, it is possible to more appropriately determine the detection timing of the offset amount according to the shape of the paper.

If the estimated tilt of the paper with respect to the main scanning direction does not match both the tilt detected by the front edge sensor 157 and the tilt detected by the rear edge tilt sensor 59, the controller 301 determines the amount of offset of the paper. It does not have to be detected. By doing so, it is possible to prevent subsequent image reading processing and image correction processing based on the offset amount on the paper for which an accurate offset amount cannot be detected.

[3. Brief Summary]
As described above, in the third embodiment, the image forming apparatus 300 further includes a rear end tilt sensor that detects the tilt of the rear end of the paper. The controller 301 compares at least one of the detected first and second tilts with the estimated tilt to determine the offset detection timing.

With the above configuration, the controller 301 can determine the offset detection location based not only on the tilt at the front edge of the paper but also on the tilt at the rear edge where there is less damage in the transport path than the front edge. Therefore, it is possible to detect the amount of offset of the paper more accurately.

<Fourth Embodiment>
[1. Overview]
Hereinafter, the fourth embodiment will be described. The fourth embodiment is different from the above embodiment in that the user can set the position of the detection target of the offset amount of the conveyed paper. The image forming apparatus according to the present embodiment is realized by the same configuration as the hardware configuration included in the image forming apparatus 100 according to the above-described embodiment. Therefore, those explanations will not be repeated.

[2. detail]
The image reading process according to the fourth embodiment will be described with reference to FIG. FIG. 16 is a diagram showing an outline of the image reading process according to the fourth embodiment.

In the example shown in FIG. 16, the end portion at the front end of the paper transported in the transport path 42 is cut off. Here, the distance between the side ends XY in the transport direction is 25 mm. The user operates the operation panel 60 to set the side end P on the rear end side (for example, a point on the rear end side 20 mm in the transport direction from the side end B) as the offset amount detection point. The controller 401 detects the offset amount of the paper S based on the output value of the side edge sensor 58 with respect to the offset amount detection location set based on the user's operation.

[3. Brief Summary]
With the above configuration, the user can set the offset amount detection location according to the shape of the paper to be conveyed, so that the accuracy of the offset detection is improved and the offset amount detection location is determined. It is possible to omit the processing by the controller for performing the subsequent processing smoothly.

<Other embodiments>
The scope of application of the technical idea according to the present disclosure is not limited to the above embodiment. For example, in the third embodiment, the image forming apparatus 300 includes the front end sensor 157 and the rear end tilt sensor 59, but may be configured to include only the rear end tilt sensor 59. In this case, the controller 301 has a side edge when the tilt estimated based on the rate of change of the output value of the side edge sensor 58 with the paper transfer and the tilt detected by the rear edge tilt sensor 59 match. Based on the output value from the sensor 58, the amount of offset of the paper is detected.

Further, in the fourth embodiment, when setting the offset amount detection location of the user, not only the shape of the paper but also the thickness may be taken into consideration. For example, if the user sets the offset amount detection location according to the shape of the paper and then inputs the type of paper thickness, the controller 401 corrects the offset amount detection location according to the type. May be good. By doing so, it becomes possible to detect the amount of deviation at a more appropriate position for thin paper that is easily damaged in transportation. Even in this way, the same effect as that of the above embodiment can be obtained.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

12 ROM, 13 RAM, 14 Communication I / F section, 15 Image data storage section, 16 Paper size storage section, 20 Image forming section, 22 Reading section, 30 Feeding section, 40 Scanner unit, 42 Conveyance path, 50 ADF unit , 51 Paper Conveyor Motor, 52 Backside Reading Means, 53 Paper Size Detection Sensor, 57,157 Front Edge Sensor, 58 Side Edge Sensor, 59 Rear Edge Tilt Sensor, 60 Operation Panel, 61 Start Button, 100, 200, 300 Image Forming Device , 101, 201, 301, 401 controller, 102 pick roller, 103 sorting roller, 104 resist roller, 105, 106, 107 roller, 108 paper ejection roller, 109 paper ejection tray, 111 separation sensor, 112 resist sensor, 113 before reading. Sensor, 114, 115 reading position, 121 paper tray, 160 empty sensor.

Claims (21)

An image processing device that reads an image on a recording medium.
The transport path to which the recording medium is transported and
With the controller
A front end sensor that detects the front end of the recording medium in the transport direction in the transport path, and
A side end sensor for detecting the side end of the recording medium in the main scanning direction intersecting the transport direction is provided.
The controller detects the amount of deviation of the recording medium in the main scanning direction based on the output value from the side end sensor at a predetermined detection timing after the timing at which the front end sensor detects the front end of the recording medium. death,
The front end sensor further detects an inclination of the front end of the recording medium with respect to the main scanning direction.
The controller
Based on the rate of change of the output value of the side end sensor with the transport of the recording medium, the inclination of the recording medium with respect to the main scanning direction is estimated.
Based on the output value from the side end sensor at the timing when the estimated inclination and the inclination detected by the front end sensor satisfy a predetermined relationship, the offset amount of the recording medium in the main scanning direction is determined. Detect and
The predetermined relationship is that the detected tilt coincides with the estimated tilt . The image processing apparatus according to claim 1 , wherein the detection timing is a timing at which the detected inclination and the estimated inclination first match after the front end sensor detects the front end. An image processing device that reads an image on a recording medium.
The transport path to which the recording medium is transported and
With the controller
A rear end tilt sensor that detects the tilt of the rear end of the recording medium in the transport direction in the transport path with respect to the main scanning direction intersecting the transport direction.
A side end sensor for detecting the side end of the recording medium in the main scanning direction is provided.
The controller
Based on the rate of change of the output value of the side end sensor with the transport of the recording medium, the inclination of the recording medium with respect to the main scanning direction is estimated.
At the timing when the estimated tilt and the tilt detected by the rear end tilt sensor match, the offset amount of the recording medium in the main scanning direction is detected based on the output value from the side end sensor. Image processing device. An image processing device that reads an image on a recording medium.
The transport path to which the recording medium is transported and
With the controller
A first tilt sensor that detects the tilt of the front end of the recording medium with respect to the main scanning direction intersecting the transport direction in the transport path.
A second tilt sensor that detects the tilt of the rear end of the recording medium with respect to the main scanning direction, and
A side end sensor for detecting the side end of the recording medium in the main scanning direction is provided.
The controller
Based on the rate of change of the output value of the side end sensor with the transport of the recording medium, the inclination of the recording medium with respect to the main scanning direction is estimated.
The main scanning direction of the recording medium is based on the output value from the side end sensor at a timing that coincides with at least one of the tilt detected by the first tilt sensor and the tilt detected by the second tilt sensor. An image processing device that detects the amount of offset in. The controller
The first estimated value and the second estimated value of the inclination of the recording medium are calculated based on the rate of change of the position of the side end detected by the side end sensor with the transportation of the recording medium.
The tilt detected by the first tilt sensor matches the first estimated value, the tilt detected by the second tilt sensor matches the second estimated value, and the tilt detected by the first tilt sensor. When the tilt detected by the second tilt sensor does not match, the main scan of the recording medium is based on the output value from the side end sensor with respect to the side edge used for calculating the second estimated value. The image processing apparatus according to claim 4 , wherein the amount of deviation in the direction is detected. In the controller, the estimated tilt is the tilt detected by the first tilt sensor and the tilt detected by the second tilt sensor according to the rate of change of the side end sensor with the transport of the recording medium. The image processing apparatus according to claim 4 , wherein it is determined which of the above is the case where the offset amount is detected. The controller determines that the estimated tilt of the recording medium with respect to the main scanning direction does not match both the tilt detected by the first tilt sensor and the tilt detected by the second tilt sensor. The image processing apparatus according to claim 4, which does not detect the offset amount. Further provided with an interface for accepting input of information for setting the position of the detection target of the offset amount on the recording medium.
When the information is input via the interface, the controller detects the amount of deviation of the recording medium in the main scanning direction based on the output value of the side end sensor with respect to the position of the detection target. , The image processing apparatus according to any one of claims 1 to 7. The image processing apparatus according to claim 8 , wherein the information is information regarding the shape of a recording medium. The image processing apparatus according to claim 8 , wherein the information is information regarding the thickness of the recording medium. The front end sensor detects the front end of the recording medium as a digital value and receives it.
The image processing device according to claim 1 or 2 , wherein the side end sensor detects the side end of the recording medium as an analog value. The image processing device includes a reading unit for reading an image on the recording medium.
The image processing apparatus according to any one of claims 1 to 11 , wherein the controller sets an area in which the reading unit reads an image on the recording medium based on the offset amount. The controller rotates the scanned image about a central point in the region on a line along the main scanning direction through the side edge detected by the side edge sensor due to the offset amount. The image processing apparatus according to claim 12 , wherein the image processing device corrects the inclination of the image by causing the image to be tilted. A method for detecting a recording medium in an image processing device that reads an image on a recording medium.
The image processing apparatus includes a transport path through which the recording medium is transported.
The detection method is
A step of detecting the front end of the recording medium in the transport direction in the transport path, and
A step of detecting the side edge of the recording medium in the main scanning direction intersecting the transport direction, and
A step of detecting an offset amount in the main scanning direction of the recording medium based on the detection result in the step of detecting the side edge at a predetermined timing after the step of detecting the front end of the recording medium .
A step of detecting an inclination of the front end of the recording medium with respect to the main scanning direction, and a step of detecting the inclination with respect to the main scanning direction.
A step of estimating the inclination of the recording medium with respect to the main scanning direction based on the rate of change of the output value of the sensor that detects the side end due to the transport of the recording medium.
The amount of deviation of the recording medium in the main scanning direction is detected based on the output value from the sensor at the timing when the estimated inclination and the inclination of the front end with respect to the main scanning direction satisfy a predetermined relationship. Including steps to do
The detection method , wherein the predetermined relationship is that the detected tilt coincides with the estimated tilt. A method for detecting a recording medium in an image processing device that reads an image on a recording medium.
The image processing apparatus includes a transport path through which the recording medium is transported.
The detection method is
A step of detecting the inclination of the rear end of the recording medium in the transport direction in the transport path with respect to the main scanning direction intersecting the transport direction.
A step of detecting the side edge of the recording medium in the main scanning direction,
A step of estimating the inclination of the recording medium with respect to the main scanning direction based on the rate of change of the output value of the sensor that detects the side edge with the transport of the recording medium.
Detection including a step of detecting an offset amount in the main scanning direction of the recording medium based on an output value from the sensor at a timing at which the estimated inclination and the inclination of the rear end coincide with each other. Method. A method for detecting a recording medium in an image processing device that reads an image on a recording medium.
The image processing apparatus includes a transport path through which the recording medium is transported.
The detection method is
A step of detecting the inclination of the front end of the recording medium with respect to the main scanning direction intersecting the transport direction in the transport path.
A step of detecting the inclination of the rear end of the recording medium with respect to the main scanning direction, and
A step of detecting the side edge of the recording medium in the main scanning direction,
A step of estimating the inclination of the recording medium with respect to the main scanning direction based on the rate of change of the output value of the sensor that detects the side edge with the transport of the recording medium.
Detection including a step of detecting an offset amount in the main scanning direction of the recording medium based on an output value from the sensor at a timing that coincides with at least one of the inclination of the front end and the inclination of the rear end. Method. A method for detecting a recording medium in an image processing device that reads an image on a recording medium.
The image processing apparatus includes a transport path through which the recording medium is conveyed, and an interface for accepting input of information for setting a position of a detection target of a biased amount in the main scanning direction of the recording medium.
The detection method is
A step of detecting the front end of the recording medium in the transport direction in the transport path, and
A step of detecting the side edge of the recording medium in the main scanning direction intersecting the transport direction, and
Includes a step of detecting an offset amount in the main scanning direction of the recording medium based on the detection result in the step of detecting the side edge at a predetermined timing after the step of detecting the front end of the recording medium. ,
The step of detecting the amount of deviation of the recording medium in the main scanning direction is the output value of the sensor that detects the side end with respect to the position of the detection target when the information is input via the interface. A detection method comprising detecting an offset amount of the recording medium in the main scanning direction based on the present invention. A control program that causes a computer to execute the detection method of the recording medium in an image processing device that reads an image on the recording medium.
The image processing apparatus includes a transport path through which the recording medium is transported.
The detection method is
A step of detecting the front end of the recording medium in the transport direction in the transport path, and
A step of detecting the side edge of the recording medium in the main scanning direction intersecting the transport direction, and
A step of detecting an offset amount in the main scanning direction of the recording medium based on the detection result in the step of detecting the side edge at a predetermined timing after the step of detecting the front end of the recording medium .
A step of detecting an inclination of the front end of the recording medium with respect to the main scanning direction, and a step of detecting the inclination with respect to the main scanning direction.
A step of estimating the inclination of the recording medium with respect to the main scanning direction based on the rate of change of the output value of the sensor that detects the side end due to the transport of the recording medium.
The amount of deviation of the recording medium in the main scanning direction is detected based on the output value from the sensor at the timing when the estimated inclination and the inclination of the front end with respect to the main scanning direction satisfy a predetermined relationship. Including steps to do
The predetermined relationship is that the detected tilt coincides with the estimated tilt . A control program that causes a computer to execute the detection method of the recording medium in an image processing device that reads an image on the recording medium.
The image processing apparatus includes a transport path through which the recording medium is transported.
The detection method is
A step of detecting the inclination of the rear end of the recording medium in the transport direction in the transport path with respect to the main scanning direction intersecting the transport direction.
A step of detecting the side edge of the recording medium in the main scanning direction, and
A step of estimating the inclination of the recording medium with respect to the main scanning direction based on the rate of change of the output value of the sensor that detects the side edge with the transport of the recording medium.
A control including a step of detecting an offset amount in the main scanning direction of the recording medium based on an output value from the sensor at a timing at which the estimated inclination and the inclination of the rear end coincide with each other. program. A control program that causes a computer to execute the detection method of the recording medium in an image processing device that reads an image on the recording medium.
The image processing apparatus includes a transport path through which the recording medium is transported.
The detection method is
A step of detecting the inclination of the front end of the recording medium with respect to the main scanning direction intersecting the transport direction in the transport path.
A step of detecting the inclination of the rear end of the recording medium with respect to the main scanning direction, and
A step of detecting the side edge of the recording medium in the main scanning direction, and
A step of estimating the inclination of the recording medium with respect to the main scanning direction based on the rate of change of the output value of the sensor that detects the side edge with the transport of the recording medium.
A control including a step of detecting an offset amount in the main scanning direction of the recording medium based on an output value from the sensor at a timing that coincides with at least one of the inclination of the front end and the inclination of the rear end. program. A control program that causes a computer to execute the detection method of the recording medium in an image processing device that reads an image on the recording medium.
The image processing apparatus includes a transport path through which the recording medium is conveyed, and an interface for accepting input of information for setting a position of a detection target of a biased amount in the main scanning direction of the recording medium.
The detection method is
A step of detecting the front end of the recording medium in the transport direction in the transport path, and
A step of detecting the side edge of the recording medium in the main scanning direction intersecting the transport direction, and
Includes a step of detecting an offset amount in the main scanning direction of the recording medium based on the detection result in the step of detecting the side edge at a predetermined timing after the step of detecting the front end of the recording medium. ,
The step of detecting the amount of deviation of the recording medium in the main scanning direction is the output value of the sensor that detects the side end with respect to the position of the detection target when the information is input via the interface. A control program comprising detecting an offset amount of the recording medium in the main scanning direction based on the present invention.

Images