JP2004098489A - Image output apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that an intervention of help of setting papers is necessitated when an image scanner is used for turning output images electronic again, thus obstructing automatic maintenance. <P>SOLUTION: In the image output apparatus represented by a laser beam printer of a rear face output type which outputs the paper onto a paper discharge tray 13 while its image recording surface is turned downward, a reversing gate part 31 for reversing faces of the paper 11 before outputted onto the paper discharge tray 13 is set. Moreover, the reversing gate part 31 is controlled to output the paper 11 with the image recording surface being turned upward in an image inspection mode. Therefore, even in the image output apparatus of the rear face output type, an inspection of the output image with the use of imaging data obtained by taking photographs by a pick-up means such as a CCD camera 14 is enabled. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image output device that outputs an image recording medium on which an image is recorded based on image data to an output tray, and particularly to the image recording medium with its image recording surface facing down, in other words, the image recording surface. The present invention relates to a so-called back-side output image output apparatus that outputs an image on an output tray with the back side up.
[0002]
[Prior art]
In the field of printing presses, printing results (output images) are inspected for the purpose of maintaining image quality of output images (print images). In recent years, there has been an increasing demand for higher image quality in laser beam printers and digital copiers equipped with such laser beam printers, and maintenance by inspection of print results is required. Further, from the viewpoint of cost reduction of maintenance, automation of maintenance work and maintenance by remote control have attracted attention.
[0003]
2. Description of the Related Art Conventionally, as an apparatus having a function for maintaining image quality, there is known an image processing apparatus configured to automatically adjust image quality based on an image difference between an original image and a copied image (for example, refer to Patent Document 1). In this image processing apparatus, standard document data for image quality adjustment is stored, an image based on the standard document data is printed on paper at the time of image quality adjustment and output, and the document image on the output paper is digitized by an image scanner. The difference between the densities of two image data at a predetermined comparison point is calculated. Then, the user tries to maintain the image quality by adjusting the parameters of each section of the copying machine according to the difference value.
[0004]
In addition, the original image data before raster development of the output product is obtained, image processing is performed in accordance with the characteristics of the reading means of the output product, and the image is inspected by comparing with the output product as reference image data. An output device is also known (for example, see Patent Document 2). In this output device, image data before raster development is obtained and image processing is performed, so that accurate data can be obtained as reference image data. It is also characterized in that the comparison is made in consideration of the deviation of the position in the output means reading means.
[0005]
[Patent Document 1]
JP-A-8-190630 (page 6-9, FIG. 5)
[Patent Document 2]
JP-A-2000-123176 (page 5-7, FIG. 3)
[0006]
[Problems to be solved by the invention]
However, in the image processing apparatus described in Patent Document 1, since an image scanner is used to re-electronically output an image, manual intervention of setting paper is required, which is a problem in terms of automatic maintenance. Further, since a standard document for image quality adjustment is set, a trigger for starting the adjustment is required, and it is impossible to constantly monitor the image quality that changes every moment.
[0007]
Further, in the output device described in Patent Document 2, when comparing the output material with the original image, if the deviation amount of the paper in the reading means of the output material is large, it is difficult to compare the corresponding positions. However, since the amount of deviation is an expected value and is different from an actual value, there is a problem that the process is complicated.
[0008]
The present invention has been made in view of the above problems, and an object of the present invention is to provide an image output apparatus that enables automation and simplification of inspection of an output image.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, an image output device according to the present invention is directed to a backside output device that outputs an image recording medium on which an image is recorded based on image data to an output tray with its image recording surface facing down. Photographing means for photographing the image recording surface of the image recording medium output on the output tray, and recording the image recording medium on the image recording medium based on image data obtained when photographing the image recording medium by the photographing means. Image inspection means for inspecting an image, reversing means for reversing the surface of the image recording medium before outputting to the output tray, and the image recording medium to be inspected by the image inspection means, with the image recording surface facing upward And control means for controlling the reversing means so as to output to the output tray.
[0010]
The image output device having the above-described configuration includes, in addition to a normal image output mode in which an image recording medium on which an image is recorded based on image data is output on an output tray with its image recording surface facing down, An image inspection mode for inspecting the output image of the image recording medium. In this image inspection mode, the image recording medium output with the image recording surface facing down is usually controlled under the control of the control unit. Then, the surface is inverted by the inversion means and output. As a result, the image recording medium is output onto the output tray with its image recording surface facing upward. Then, an image of the image recording surface of the image recording medium is photographed by the photographing means, and the image inspection means inspects the output image based on the photographed data. As a result, even in an image output apparatus that outputs an image recording medium on an output tray with the image recording surface facing down, it is possible to inspect the output image using the image data obtained by the imaging unit.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic external view showing a configuration of a main part of an image output device, for example, a printer device according to an embodiment of the present invention.
[0012]
The printer device 10 according to the present embodiment is a normal image output mode in which an image recording medium on which an image is recorded based on image data, for example, paper 11 is output from a paper discharge unit 12 to a paper discharge tray (output tray) 13. The paper 11 is output on the paper discharge tray 13 with the image recording surface facing down, in other words, with the back side of the image recording surface facing up (hereinafter referred to as “back surface output”). As shown in FIG. 1, the printer 10 according to the present embodiment is configured to output an image of the sheet 11 output on the sheet discharge tray 13 in the image inspection mode in order to realize a process for image inspection described later. A photographing means for photographing the recording surface, for example, a CCD (Charge Coupled Device) camera 14 installed above the paper discharge unit 12 is provided.
[0013]
By the way, in recent image output apparatuses, especially printer apparatuses typified by laser beam printers, the above-mentioned back side output type is increasing. For example, in a print job composed of a plurality of outputs, a print job described in a page description language (PDL) or the like is output under the control of a printer controller (not shown) of the printer apparatus 10 under the control of a printer controller (not shown). The back side output processing is sequentially performed from the top.
[0014]
As described above, in the back side output type printer, the print job is sequentially output on the paper discharge tray 13 from the top of the page so that the user does not need to replace the page after the print job output process is completed. The advantage is that the print output in the page order of the print job can be received sequentially from the top of the page.
[0015]
The printer device 10 according to the present embodiment is provided with a paper transport system having a configuration for realizing the above-described back side output. It is characterized in that a reversing means for appropriately reversing the surface of the sheet (image recording medium) 11 is provided in the sheet transport system. Hereinafter, the configuration of the paper transport system will be described with a specific example.
[0016]
[First specific example]
FIG. 2 is a schematic configuration diagram illustrating a first specific example of a sheet transport system in the printer device 10 according to the present embodiment. Hereinafter, the operation of the paper transport system according to this specific example will be described.
[0017]
2, a sheet set in a sheet feed tray 21 is fed to a photosensitive drum 28 via a pickup roll 22, a feed roll 23, a retard roll 24, a takeaway roll 25, a pre-registration roll 26, and a registration roll 27. Then, the image on the photosensitive drum 28 is transferred onto the paper. Here, the image recording surface of the paper is on the upper side of the figure. The recording paper on which the image has been transferred is sent to a reversing unit, for example, a reversing gate unit 31 via a fixing unit 29 and a fixing unit discharge roll 30. In the normal print output (image output) mode, the reversing gate unit 31 sends out the sheet to the triroll 32 to perform the sheet reversing process.
[0018]
Next, the operation of the tri-roll 32 and the reversing roll 33 when reversing the sheet will be described. When the first sheet is carried in, the roll 32L and the reversing roll 33 on the left side of the tri-roll 32 are rotated forward to feed the sheet to the lower side in the figure. Thereafter, the reversing roll 33 is reversed, and the paper is fed until the leading end of the paper reaches the right roll 32R of the tri-roll 32. When the leading end of the paper rolls on the right roll 32R of the tri-roll 32, the right roll 33R of the reversing roll 33 is separated from the left roll 33L, and the reversing roll 33 is rotated forward so that the second sheet can be carried in.
[0019]
By performing the above-described series of operations, the recording paper whose image recording surface was on the upper side when it exited the fixing unit 29 is turned downward by the reversing operation of the tri-roll 32 and the reversing roll 33. Is output on the paper discharge tray 13 via the discharge roll 34. Therefore, in the image inspection mode, since the image recording surface of the paper needs to be on the paper discharge tray 13, it is necessary to reverse the paper surface before outputting the image on the paper discharge tray 13. In FIG. 2, the paper transport path is shown by a dashed line.
[0020]
Next, a description will be given of sheet conveyance during image defect detection processing to be described later in the image inspection mode. The operation up to the inversion gate section 31 is the same as that described above, and the description thereof will be omitted because it is redundant. In the image inspection mode, the recording paper is sent directly to the discharge roll 34 instead of the reversing roll 33 side under the control of the reversing gate unit 31 and is output on the paper discharge tray 13 with the image recording surface facing upward (front side output). . The image recording surface of the recording sheet output on the sheet discharge tray 13 with the image recording surface facing upward is photographed by the CCD camera 14, and a predetermined defect detection process described later is performed based on the image data. In FIG. 2, the paper transport path is indicated by a broken line.
[0021]
[Second specific example]
FIG. 3 is a schematic configuration diagram illustrating a second specific example of the sheet transport system in the printer device 10 according to the present embodiment. Hereinafter, the operation of the paper transport system according to this specific example will be described.
[0022]
In FIG. 3, a sheet set in a sheet feed tray 41 is fed to a photosensitive drum 47 via a pickup roll 42, a feed roll 43, a retard roll 44, a takeaway roll 45, and a registration roll 46, and is fed to the photosensitive drum 47. The image on the drum 47 is transferred onto the paper. In FIG. 3, the image recording surface of the paper is on the right side of the figure.
[0023]
The recording paper on which the image has been transferred is sent to the reversing gate unit 50 via the fixing device 48 and the fixing device discharge roll 49. In a normal print output mode (image output mode), the reversing gate unit 50 sends out a sheet to the discharge roll 52 side. In this case, the image recording surface on the right side is lower on the output tray 13 during paper transport. Therefore, in the image inspection mode, since the image recording surface of the paper needs to be on the paper discharge tray 13, it is necessary to reverse the paper surface before outputting the image on the paper discharge tray 13.
[0024]
Next, a description will be given of sheet conveyance during image defect detection processing to be described later in the image inspection mode. In the image inspection mode, the reversing gate unit 50 sends the recording paper to the reversing roll 51 side. The reversing roll 51 conveys the recording paper to the left side of the reversing roll 51 by normal rotation, then reverses the rotation direction and sends the paper to the discharge roll 52 side. In this case, the image recording surface, which was on the right side during the paper transport, becomes an upper side on the output tray 13. The image recording surface of the recording sheet output on the output tray 13 with the image recording surface facing upward is photographed by the CCD camera 14, and a predetermined defect detection process described later is performed based on the image data.
[0025]
FIG. 4 is a block diagram illustrating a configuration example of an image inspection device mounted on the printer device 10 according to the present embodiment. The image inspection apparatus according to this configuration example is configured as a part of a print processing system of a printer device 10, for example, a laser beam printer.
[0026]
4, the print processing system 60 according to this configuration example includes a CPU 61, a RAM 62, a hard disk drive (HDD) 63, an external interface (hereinafter, referred to as “I / F”) circuit 64, and an image output unit ( It has an IOT (Image Output Terminal) controller (hereinafter referred to as an “IOT controller”) 65 and a CCD camera I / F circuit 66, which are interconnected via a data bus 67. The CPU 61 is connected to a ROM 68 for storing programs. The CCD camera 14 is connected to the CCD camera I / F circuit 66 as the above-described photographing means.
[0027]
The CPU 61 appropriately reads out a program stored in the ROM 68 and mainly performs a printing process. The CPU 61 also has a function as an image processing unit and an abnormality detection unit included in the image inspection apparatus. A determination process and an image inspection process are performed. Further, image data for print processing and image inspection processing is transmitted and received to and from other hardware via the data bus 67.
[0028]
The RAM 62 includes an area required for print processing, that is, a work area for print processing, and a buffer area for storing image data (image data obtained by developing print data in a bitmap) to be transmitted to the IOT controller 65 after print processing. Further, it includes an area required for image inspection processing, that is, a work area for performing image processing for output inspection, and a buffer area for storing image data obtained by photographing with the CCD camera 14.
[0029]
The hard disk of the hard disk device 63 (hereinafter, referred to as “hard disk 63”) stores an area for storing print data input from the outside via the external I / F circuit 64 and develops the print data into a bitmap. (Rasterization) and an area for storing one sheet of image data after print processing generated.
[0030]
The interface unit of the external I / F circuit 64 is, for example, a parallel port connected to a printer port of a PC (personal computer) or an Ethernet (R) interface, and is a printer described in PDL (page description language). Input data for external use.
[0031]
The IOT controller 65 is an interface circuit with an image output unit (IOT) (not shown) that prints an image on paper using an electrostatic latent image using a light beam from a laser light source and outputs the image. The image data that has been developed and stored in the RAM 62 is rearranged in the processing order by the image output unit, and the image output unit is controlled to generate a signal of the laser light source.
[0032]
The CCD camera I / F circuit 66 converts the analog imaging signal output from the CCD camera 14 into digital imaging data from analog to digital, and stores the digital imaging data in the RAM 62. As shown in FIG. 1, the CCD camera 14 is installed above the paper discharge unit 12 in the printer device 10 so that the entirety of the paper discharge tray 13 can be set as a photographing range.
[0033]
The paper discharge tray 13 is colored in a color different from the color of the paper 11. This is based on the photographing result of the CCD camera 14, the state of the sheet discharge tray 13 when the sheet 11 is present and the state of the sheet discharge tray 13 when the sheet 11 is not present, in other words, the state of the sheet 11 on the sheet discharge tray 13. This is because it is possible to easily determine whether or not there exists.
[0034]
The RAM 62 stores image data (hereinafter, referred to as “tray image data”) obtained by photographing the entire sheet discharge tray 13 with the CCD camera 14 in a state where the sheet 11 is not present on the sheet discharge tray 13. It shall be stored in advance.
[0035]
Further, in the printer device 10 according to the present embodiment, the discharge position (output position) of the paper 11 on the paper discharge tray 13 is shifted and output for each print job.
[0036]
Next, an example of processing for detecting an image defect in the print processing system having the above configuration will be described.
[0037]
<Processing example 1>
First, a processing procedure of a control routine of the printer device 10 executed by the CPU 61 will be described with reference to a flowchart of FIG. First, the CPU 61 determines whether or not print data input from the outside via the external I / F circuit 64 has been received as a print job (step S11). The processing shifts to the standby state for output processing).
[0038]
In the standby state of the print processing, the elapse of a predetermined time is monitored (step S12), and after the elapse of the predetermined time, image inspection availability determination processing is executed (step S13). That is, in the print processing standby state, the image inspection availability determination processing is periodically executed at predetermined time intervals.
[0039]
FIG. 6 shows a processing flow of a subroutine for executing the image inspection availability determination processing. As shown in the flowchart of FIG. 6, in the image inspection availability determination processing, first, an instruction to start photographing is sent to the CCD camera 14 (step S21). In response to this instruction, the CCD camera 14 photographs the entire sheet discharge tray 13. An analog image signal obtained by photographing with the CCD camera 14 is converted into digital image data (hereinafter, referred to as “imaging data”) in the CCD camera I / F circuit 66 and stored in the RAM 62.
[0040]
Next, the imaging data acquired by the photographing instruction is compared with the image data of the tray stored in the RAM 62 in advance (step S22), and the paper 11 is present on the paper discharge tray 13 based on the comparison result. It is determined whether or not (step S23). If the sheet 11 is present on the sheet discharge tray 13, it is determined that the image inspection is impossible, and the image inspection enable flag indicating that the image inspection is possible is turned off (step S24). Thereafter, the process returns to the main control routine of FIG. Continue the state.
[0041]
On the other hand, if the sheet 11 does not exist on the sheet discharge tray 13, it is determined that the image inspection is possible, and the image inspection possible flag is turned ON (step S25). Thereafter, the process returns to the main control routine to continue the standby state. That is, in the printer device 10, the CPU 61 periodically performs the main image inspection availability determination process in the standby state of the print process, thereby periodically photographing the state of the sheet discharge tray 13 and setting the image inspection enable flag. The determination result of the image inspection, which is identified by ON / OFF, is updated as needed.
[0042]
In this processing example, it is determined whether or not there is a sheet on the sheet discharge tray 13 based on the result of photographing by the CCD camera 14. However, a dedicated method for detecting the presence or absence of a sheet on the sheet discharge tray 13 is described. May be provided, and whether or not a sheet is present on the sheet discharge tray 13 may be determined based on the detection result of the sensor. However, if a dedicated sensor is used, the number of parts increases accordingly, and in order to reduce the cost, it is preferable to use the photographing result of the CCD camera 14.
[0043]
If the CPU 61 determines in step S11 in FIG. 5 that print data input from the outside via the external I / F circuit 64 has been received as a print job, the CPU 61 shifts from the standby state to the print state. Then, a print control process is executed (step S14).
[0044]
FIG. 7 shows a processing flow of a subroutine for executing the print control processing. As shown in the flowchart of FIG. 7, in the print control process, first, the state of the image inspection enable flag is determined (step S31). If the image inspection possible flag is OFF, it is determined that the image inspection is not possible, and based on the received print job, the image data after the development of each page is output to the IOT controller 65 to perform a normal print process (step S32). ). After the printing process is completed, the process returns to the main control routine and returns to the standby state.
[0045]
On the other hand, if the image inspection possible flag is ON, it is determined that the image inspection is possible, and based on the received print job, only the first print processing is performed, and the image data at this time is stored in the hard disk 63. (Step S33). More specifically, the image data after the development of the first page is sent to the IOT controller 65, the image data is stored in the hard disk 63, and an instruction is sent to the IOT controller 65 to print only one sheet. Only the printer processing of the sheet is performed.
[0046]
Next, an image inspection process described later is started (step S34). If the received print job is a print job instructing printing of a plurality of sheets, the image inspection process is performed in parallel with the image inspection process based on the print job. The remaining print processing is performed (step S35). Here, a plurality of prints means a print of a plurality of pages, a print of only one page but a plurality of copies, a print of a plurality of pages of a plurality of copies, and the like. After the printing process is completed, the process returns to the main control routine and enters a standby state. Note that the print processing and the image inspection processing may be time-division sequential processing.
[0047]
FIG. 8 shows a processing flow of a subroutine for executing the image inspection processing. As shown in the flowchart of FIG. 8, in the image inspection process, first, a notification of the completion of the first print processing from the IOT controller 65 is waited (step S41), and when the notification is received, a predetermined time, that is, after the print processing, After the time required for the paper to be discharged to the paper discharge tray 13 has elapsed, a photographing instruction is sent to the CCD camera 14 (step S42).
[0048]
In response to this photographing instruction, the CCD camera 14 photographs the state immediately after the first sheet after printing is discharged from the state where there is no sheet on the sheet discharge tray 13. An analog image signal output from the CCD camera 14 by this photographing is converted into digital image data (imaging data) in the CCD camera I / F circuit 66 and stored in the RAM 62.
[0049]
Subsequently, the image data stored in the RAM 62 is subjected to brightness correction (shading correction) based on correction data created in advance by, for example, photographing a blank sheet during maintenance and stored in the RAM 62 or the hard disk 63. ) (Step S43), and then optical distortion correction (step S44), and then shape correction from a trapezoid to a rectangle (perspective transformation processing) (step S45).
[0050]
Here, the correction of the optical distortion refers to correcting the distortion of the lens of the CCD camera 14. Assuming that the distance from the lens to the imaging plane is c and the distance of the imaging position on the imaging plane from the optical axis is r, the aberration d at the angle of incidence θ to the lens is generally expressed by the following equation.
[0051]
d = r≡ctan θ
The optical distortion is corrected based on the characteristic of the aberration d of the lens. Alternatively, since the aberration d is generally proportional to the cube of the distance r of the image-forming position on the image-forming surface from the optical axis, it is also possible to correct the optical distortion by obtaining a proportional constant based on the lens characteristics. It is.
[0052]
Further, shape correction from a trapezoid to a rectangle refers to correcting geometric distortion included in imaging data. Image data obtained by photographing with the CCD camera 14 is obtained by projecting a three-dimensional space onto a two-dimensional plane, and the CCD camera 14 installed as shown in FIG. Therefore, as the distance from the CCD camera 14 in the direction of the line of sight increases, a longer horizontal dimension orthogonal to the direction of the line of sight is projected on the two-dimensional plane, causing geometric distortion. Because of the geometric distortion, the paper on the paper discharge tray 13 is projected into a trapezoidal shape, and is converted into a rectangular shape, which is the original paper shape, by shape correction. This shape correction makes it possible to associate the paper area of the imaging data with the original image data.
[0053]
Next, as the specific processing, the color of the background paper discharge tray 13 and the color of the edge of the paper (generally, since the printing is not performed on the edge of the paper, Is used to specify the position (area) of the sheet, cut out only the specified sheet area from the image data after the correction processing, and use the cut-out result as image data for comparison in the RAM 62. (Step S46).
[0054]
In this processing example, the paper area is cut out from the image data after the correction processing in order to reduce the memory capacity and speed up the comparison processing (difference processing) with the original image data described later. If the area can be specified, comparison with the original image data is possible. Therefore, the coordinates of the specified paper area may be stored, and the cutout of the paper area may be omitted.
[0055]
At this time, if image pickup data obtained by photographing a state in which another sheet such as a sheet discharged by a previous print job is present on the sheet discharge tray 13 is used, there is a concern that the image may be cut out including an area of another sheet. is there. However, in the present processing example, as described above, the imaging data immediately after the first sheet is discharged from the state where there is no sheet on the sheet discharge tray 13, that is, one sheet is stored on the sheet discharge tray 13. Since the imaging data obtained by photographing only a certain state is used, the paper area can be easily specified and cut out only by the color difference without considering the deviation amount of the paper.
[0056]
That is, as shown in FIG. 9A, image data obtained by photographing a state in which a sheet is present on the sheet discharge tray 13 by the CCD camera 14 is corrected for optical distortion to correct lens distortion. By the shape correction, the shape of the paper area on the imaging data is adjusted. Then, a paper area is specified from the image data after the correction processing, and only the specified paper area is cut out to generate image data for comparison.
[0057]
Next, the resolution of the image data (hereinafter, referred to as “original image data”) stored in the hard disk 63 and used for the first printing process is determined according to the resolution of the CCD camera 14 using a linear interpolation method or the like. A resolution conversion process for conversion is performed (step S47). Next, blurring processing (Gaussian filter processing) for intentionally adding blur due to the optical system of the CCD camera 14 and blur due to optical distortion correction and shape correction to the original image data after the resolution conversion processing. That is, a process for deteriorating the image sharpness is performed, and the result is stored in the RAM 62 as original image data for comparison (step S48).
[0058]
That is, as shown in FIG. 9B, the original image data is adjusted to the resolution of the image data obtained by the CCD camera 14 by the resolution conversion process, and is substantially equivalent to the blur included in the image data after the image processing by the blur process. They are equally blurred and generated as original image data for comparison.
[0059]
It should be noted that the original image data is used when it is sent to the IOT controller 65, and the characteristics at the time of printing (image output) by the image output unit have already been taken into account. For this reason, here, a case is shown in which image processing is performed on the original image data in consideration of only the characteristics at the time of shooting with the CCD camera 14, but the image data before expansion is used as the original image data, The image processing may be performed in consideration of the characteristics of the photographing and the characteristics at the time of photographing.
[0060]
However, when the image data before the expansion is used as the original image data, the CPU 61 needs to perform the expansion at the time of transmission to the IOT controller 65 and also at the time of the image processing for generating the original image data for comparison. is there. Therefore, in order to reduce the processing time, it is preferable to use the image data after expansion when transmitted to the IOT controller 65 as the original image data as in the present processing example.
[0061]
In this way, by performing image processing on the image data and the original image data, the image characteristics of the two, that is, the resolution, the shape, and the sharpness are adjusted to be substantially equal. In other words, comparison imaging data and comparison original image data having substantially the same image characteristics are generated.
[0062]
Thereafter, a difference process is performed between the generated comparison image data and the comparison original image data (step S49). If the cut-out processing is omitted, each pixel of the original image data is associated with a pixel of the imaging data based on the coordinates of the stored paper area, and the difference between the corresponding pixels may be obtained. .
[0063]
As a result of this difference processing, if there is a defect pattern such as a black point on the print output, that is, on the imaging data side, the black point remains in the difference result. Therefore, a defect detection process is performed by setting an appropriate density threshold and binarizing the difference result using the threshold (step S50). By this defect detection processing, image defects such as black spots can be detected.
[0064]
When an image defect is detected, a warning is issued on a user interface (not shown) such as a display panel provided in the printer device 10 or an external device such as a cable or the like is connected via the external I / F circuit 64. It is also possible to issue a warning to a PC that is going to execute printing using a network or to notify a printer maintenance company through a network when a remote maintenance system or the like is constructed.
[0065]
Note that, in the present processing example, the case where a local image result such as a black point is detected has been described as an example. It is also possible to detect a poor image quality such as density and density fluctuation.
[0066]
In this processing example, in the image inspection processing, first, image processing is performed on the imaged data to generate imaged data for comparison, and then image processing is performed on the original image data to generate the original image for comparison. Although the data is generated, the processing on the imaging data and the original image data may be performed in parallel.
[0067]
Further, the processing for detecting an image defect is not limited to the above processing example. Hereinafter, other processing examples will be described.
[0068]
<Processing example 2>
In the processing example 1, the case where the shape correction is performed on the imaging data side in order to compare the imaging data with the original image data in the image inspection processing has been described as an example. On the other hand, in processing example 2, shape correction is performed on the original image data side. FIG. 10 shows a flow of the image inspection processing according to the processing example 2. In FIG. 10, the same processes as those in FIG. 8 are denoted by the same step numbers, and the details of each process are redundant, and therefore description thereof will be omitted.
[0069]
As shown in the flowchart of FIG. 10, optical distortion is corrected for the imaging data (step S44), and then a paper area in which the paper area is specified is cut out, and stored in the RAM 62 as comparison imaging data (step S44). Step S45). Thus, a trapezoidal paper area is cut out as comparison imaging data.
[0070]
The original image data is subjected to a resolution conversion process (step S47), and then the shape is converted from a rectangle to a trapezoid (step S45). By the conversion process from the rectangle to the trapezoid, the geometric distortion included in the image data is intentionally added to the original image data, and the original image data can be associated with the shape of the paper area cut out in step S46. Then, the image is subjected to a blurring process and stored in the RAM 62 as original image data for comparison (step S48).
[0071]
As a result, image data that has been converted into a trapezoidal shape in accordance with the comparison image data is generated as the comparison original image data. In step S49, the difference processing between the comparison image data and the original image data is performed. It can be performed. As in the processing example 1 in which the image data is converted in shape by this difference processing, if a defect pattern such as a black point exists on the image data, a black point remains in the difference result, so that an image defect can be detected. it can.
[0072]
<Processing example 3>
In the first processing example, the image defect is detected by the image inspection process only for the first print processing result in one print job to perform the defect determination. However, as described above, the imaging data and the original image are determined. Since an image defect is detected by performing a difference process after correcting each data, an erroneous determination may occur due to a correction error or a threshold used when detecting the defect. Processing example 3 is made in view of this point. In the processing example 3, the pixel wing defect is detected not only by the result of the print processing of the first sheet but also by the image inspection processing on the results of the print processing of a plurality of sheets to determine the defect.
[0073]
FIG. 11 shows, as an example, a flow of a subroutine for executing a print control process according to a process example 3 in which, in one print job, image defects are detected for all print processing results to determine a defect. Is shown.
[0074]
In the print control process shown in FIG. 11, when the print job is received and the print process is performed, first, the state of the image inspection enable flag is determined (step S51). If the image inspection possible flag is OFF, it is determined that the image inspection is not possible, and normal print processing is performed based on the received print job (step S52), and thereafter, the process returns to the main control routine.
[0075]
On the other hand, if the image inspection possible flag is ON, it is determined that the image inspection is possible, and the first print processing is performed (step S53), and then the image inspection processing is performed to detect a defect in the print processing result (step S53). Step S54). As the image inspection process executed here, the image inspection process shown in FIG. 8 may be used, or the image inspection process shown in FIG. 10 may be used. Then, the print process (step S53) and the image inspection process (step S54) are repeatedly executed one by one until it is determined that all the print processes specified in the print job received in step S55 are completed.
[0076]
In one print job, the position of the output paper on the paper discharge tray 13 is constant, and therefore, the specification of the paper area, that is, the detection of the cutout position of the paper area is sufficient for only the first sheet. The same coordinate values can be used from the first sheet. After the print processing for each sheet, only the resolution conversion of the original image and the photographing by the CCD camera 14 are performed, and the original image data (after the resolution conversion) and the imaging data obtained by these are temporarily stored in the hard disk 63. Alternatively, each processing may be performed after the print job is completed.
[0077]
When all the print processes specified in the print job are completed, a defect determination is performed based on the result of the defect detection process for all pages (step S56). That is, for a defect pattern detected from the print processing result of each page, for example, if the same defect pattern is present in more than half of the other pages in the print job, it is determined that there is an image defect. Since there is a possibility, it can be determined that there is no image defect. Note that the criterion of half or more pages used here is used as an example, and the criterion can be set arbitrarily.
[0078]
<Processing example 4>
In the processing example 1, the case where the image defect is detected by performing the difference processing between the original image data and the imaging data has been described as an example. On the other hand, in the processing example 4, image data in which all of one page are white (all white pages) or black (all black pages) are prepared as standard image data for image inspection. Thus, when the printer device is in the standby state, the image defect is detected without performing the difference processing.
[0079]
An image defect inspection according to the fourth processing example can be performed by issuing a test print instruction from a user interface in the case of a stand-alone copying machine or a printer or from a remote place in a case of a network-connected printer. . FIG. 12 shows a flow of a subroutine executed by an image inspection process according to a process example 4 executed by the CPU 61 in response to a test print instruction.
[0080]
As shown in the flowchart of FIG. 12, in the image inspection process according to the process example 4, when a test print instruction is received in the standby state (step S61), first, the state of the image inspection enable flag is determined (step S62). ). If the image inspection possible flag is OFF, it is determined that the image inspection is impossible, and information indicating that the test is impossible is transmitted (step S63).
[0081]
In this process, for example, the user is notified that the test is not possible via the user interface, or information indicating that the test is not possible is sent to the outside via the external I / F circuit 64, for example, through a cable or network. It is also possible to notify the PC connected to the printer device 10 of a test print commanded via the printer device 10 via a network, or to a maintenance company of the printer device 10 via a network when a remote maintenance system is constructed. is there.
[0082]
If the image inspection possible flag is ON, a printing process is performed based on the image data of the all-white page (step S64). The all-white image data may be stored in the hard disk 63, or may be generated inside the system at the time of print processing.
[0083]
Then, an image inspection process is performed on the print processing result of the all-white page. More specifically, it waits for a notification of the completion of the printing process from the IOT controller 65 (step S65), and upon receiving the notification, sends an instruction to start photographing to the CCD camera 14 after a predetermined time (step S66). In response to this instruction, the CCD camera 14 captures an image of the sheet after the print processing, that is, the state immediately after the all-white pages are discharged onto the sheet discharge tray 13. An analog image signal output from the CCD camera 14 by this photographing is converted into digital image data (imaging data) in the CCD camera I / F circuit 66 and stored in the RAM 62.
[0084]
Then, image processing is performed on the imaging data stored in the RAM 62 to extract a paper area. Specifically, first, light and dark correction (shading correction) is performed (step S67), optical distortion correction is performed (step S68), and shape correction from trapezoid to rectangle is performed (step S69). A process of cutting out only the specified paper area is performed (step S70). This cutout result is stored in the RAM 62.
[0085]
Next, a defect detection process is performed using the cutout result (step S71). In this defect detection process, since the cutout result, that is, the imaged data obtained by cutting out the paper area is white over the entire cutout paper area if there is no image defect, binarization is performed by using an appropriate density as a threshold value. In addition, comparison with the original image data of an all-white page can be performed, and image defects such as black spots and black lines can be detected.
[0086]
Note that, here, an example has been described in which all white pages are printed and image defects such as black points and black lines are detected. However, the present invention is not limited to this. The processing may be performed to detect an image defect such as a white point or a white line, or the print processing and the image defect detection of an all-white page and an all-black page may be performed successively.
[0087]
Also, the pages need not be all white or all black pages. For example, a gray page having a predetermined density is printed, processed in the same manner as above, and determined to be higher or lower than a predetermined density range, so that an image defect of a black point or a black line and an image defect of a white point or a white line are determined. An image defect can also be detected at the same time. That is, a threshold value corresponding to test image data (original image data) such as all white, all black, and gray pages is obtained in advance, and the threshold value is compared with image data obtained by cutting out a paper area to detect an image defect. Processing can be performed.
[0088]
Then, finally, the detection result is transmitted (step S72). Specifically, for example, when an image defect is detected, a warning is issued to a user on a user interface (not shown) such as a display panel provided in the printer device 10 or an external I / F circuit is provided. A warning is issued to the outside via the network 64, for example, to a PC connected to the printer device 10 via a cable or a network for instructing a test print, or via a network when a remote maintenance system is constructed. It is also possible to notify the maintenance company of the printer device 10 by using this method.
[0089]
As described above, in the back side output printer device 10 that outputs the paper 11 on the paper output tray 13 with the image recording surface thereof facing down, the surface of the paper 11 before being output onto the paper output tray 13 is inverted. In the image inspection mode in which the reversing means (reversing gates 31 and 50) are provided and the image of the paper 11 output on the paper discharge tray 13 is inspected, the paper 11 is output with its image recording surface facing upward. By controlling the reversing means, the output image can be inspected using a photographing means such as the CCD camera 14 even in the case of a back side output printer.
[0090]
In addition, a CCD camera 14 is installed above the paper discharge unit 12, and the entire upper surface of the paper discharge tray 13 is photographed by the CCD camera 14, so that an image including the paper 11 discharged onto the paper discharge tray 13 is captured. Since data is acquired and the output image is inspected, there is no need for manual intervention to set and read the output image on the scanner as in the conventional technology, and the output image inspection is completely automated. can do.
[0091]
In addition, since the image characteristics of the image data and the image characteristics of the original image data are made to be substantially equal by image processing, a difference between the two image data is obtained, or the image data is set to a threshold value corresponding to the value of the original image data. The defect of the image can be detected only by a simple process such as comparison with the above.
[0092]
Further, in a state where the first sheet of paper 11 after the print processing by the print job received immediately after the state where the sheet 11 is not on the sheet discharge tray 13 is discharged, the entire sheet discharge tray 13 is photographed by the CCD camera 14. However, since the output image is inspected using the image data, there is no need to consider the deviation of the discharge position unlike the related art. Further, at this time, since the color of the paper discharge tray 13 is different from the color of the paper 11, the paper area can be easily specified from the image data obtained by the CCD camera 14.
[0093]
In the above processing examples 1 to 4, the case of detecting a partial image defect such as a point defect or a linear defect as an image abnormality has been described as an example. The present invention is not limited to the detection of a defect, and it is a matter of course that an abnormality of an entire image may be detected. As a specific example in that case, for example, a specific density pattern is added to the original image data, and the density of a location corresponding to the added specific density pattern in the imaging data is inspected to obtain an appropriate image output. A configuration for judging whether or not it has been performed can be considered.
[0094]
Further, in the above processing examples 1 to 4, in the CPU 61 performing the print processing, the image processing such as performing various corrections on the image data and the image processing such as the resolution conversion processing on the original image data are also assumed to be software processing. However, the present invention is not limited to this. That is, it is also possible to execute these image processes using a dedicated image processing circuit.
[0095]
According to this, the image processing is accelerated by the hardware processing, the CPU 61 executes the printing processing, and the image processing circuit executes the image processing for image inspection. (Instead of the parallel processing), the processing time can be shortened. In particular, the process of continuously performing image inspection described in Process Example 3 can be applied to a high-speed output printer.
[0096]
Specifically, for example, as shown in FIG. 13, in the system shown in FIG. 4, an image processing LSI 71 to which a work RAM 72 is connected is further connected to the data bus 67, thereby Can be realized. Note that the work RAM 72 can be built in the LSI 71. In this case, the CPU 61 has the function of the control unit, and the LSI 71 has the functions of the image processing unit and the image inspection unit.
[0097]
Further, the present invention has been described by taking as an example a case where the present invention is applied to the printer device 10 including the image inspection apparatus according to the above-described processing examples 1 to 4. However, the present invention is not limited to this application example, and the paper transport tray The present invention can be applied to any image output apparatus having an image inspection device configured to have an image capturing device such as a CCD camera 14 for capturing an image of the entire device 13 and inspect an image recorded on the sheet 11 based on the image data.
[0098]
Further, in the paper transport system according to the first and second specific examples described above, in the normal image output mode, the reverse side of the sheet immediately before output is inverted by the operation of the inversion gates 31 and 50 to output the back side. In the image inspection mode, it is assumed that the paper is output with its image recording surface facing up by not operating the reversing gate units 31 and 50, but the present invention is not limited to this.
[0099]
That is, in a normal image output mode, the present invention is also applicable to a paper transport system of a type in which the reverse side of the paper is output from the stage of transport without operating the reversing gate units 31 and 50. In this case, in the image inspection mode, the reversing gates 31 and 50 are operated to reverse the surface of the sheet immediately before output, thereby outputting the sheet with its image recording surface up. .
[0100]
【The invention's effect】
As described above, according to the present invention, in an image output apparatus of a back side output in which an image recording medium is output with an image recording surface thereof facing down on an output tray, the image recording medium before being output on the output tray A reversing means for reversing the surface of the sheet is provided, and in the image inspection mode, the reversing means is controlled so as to output the image recording medium with the image recording surface thereof facing upward, so that image output of a back side output type is performed. Even with the device, the inspection of the output image using the photographing means can be performed automatically and simply without any manual intervention.
[Brief description of the drawings]
FIG. 1 is a schematic external view showing a configuration of a main part of an image output device, for example, a printer device according to an embodiment of the present invention.
FIG. 2 is a schematic configuration diagram illustrating a first specific example of a paper transport system in the printer device according to the embodiment.
FIG. 3 is a schematic configuration diagram illustrating a second specific example of a sheet transport system in the printer device according to the embodiment.
FIG. 4 is a block diagram illustrating a configuration example of a print processing system mounted on the printer device according to the embodiment.
FIG. 5 is a flowchart illustrating a processing procedure of a control routine of the printer device according to the embodiment.
FIG. 6 is a flowchart showing a flow of a subroutine for executing image inspection availability determination processing;
FIG. 7 is a flowchart illustrating a flow of a subroutine for executing a print control process.
FIG. 8 is a flowchart illustrating a flow of a subroutine for executing an image inspection process according to a process example 1;
FIG. 9 is a conceptual diagram showing image processing performed on image pickup data (A) and original image data (B) in the image inspection processing according to processing example 1;
FIG. 10 is a flowchart illustrating a flow of a subroutine for executing an image inspection process according to a process example 2;
FIG. 11 is a flowchart illustrating a flow of a subroutine for executing a print control process according to a process example 3;
FIG. 12 is a flowchart illustrating a flow of a subroutine executed by an image inspection process according to a process example 4;
FIG. 13 is a block diagram illustrating another configuration example of the print processing system.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Printer apparatus, 11 ... Paper (image recording medium), 13 ... Paper discharge tray, 14 ... CCD camera, 28, 47 ... Photosensitive drum, 31, 50 ... Inversion gate part, 60 ... Print processing system, 61 ... CPU, 62 RAM 62, 63 Hard disk drive (HDD), 64 External I / F (interface) circuit, 65 IOT controller, 66 CCD camera I / F circuit

Claims (10)

An image output device that outputs an image recording medium on which an image is recorded based on image data to an output tray with its image recording surface facing down,
Photographing means for photographing an image recording surface of the image recording medium output on the output tray,
Image inspection means for inspecting an image recorded on the image recording medium based on imaging data obtained at the time of imaging of the image recording medium by the imaging means,
Reversing means for reversing the surface of the image recording medium before outputting to the output tray,
An image output apparatus comprising: a control unit that controls the reversing unit so that an image recording medium to be inspected by the image inspection unit is output to the output tray with its image recording surface facing upward. The reversing means outputs the image recording medium to the output tray with the image recording surface facing down in the non-image inspection mode by the image inspection means by not reversing the image recording medium, and in the image inspection mode by the image inspection means. 2. The image output apparatus according to claim 1, wherein the image recording medium is inverted to output the image to the output tray with its image recording surface facing upward. In the non-image inspection mode by the image inspection means, the image recording medium is inverted to output the image recording surface downward to the output tray in the non-image inspection mode by the image inspection means, and in the image inspection mode by the image inspection means, 2. The image output device according to claim 1, wherein the image recording medium is output to the output tray with its image recording surface facing upward by not inverting the image recording medium. The image inspection unit is an image processing unit that performs image processing on at least one of the image data and the imaging data so as to make the image characteristics substantially equal to each other. 2. The image output apparatus according to claim 1, further comprising an abnormality detecting unit configured to detect an abnormality of an image recorded on the image recording medium based on the image data and the image data. The image inspection unit has a determination unit that determines whether the image recording medium is present on the output tray in a standby state of image output, and after the determination unit determines that the image recording medium is not present, 5. The image output apparatus according to claim 4, wherein an image is inspected using image data obtained by photographing an image recording medium output first on said output tray by said photographing means. 6. The image output apparatus according to claim 5, wherein the determination unit determines whether an image recording medium is present on the output tray based on image data obtained by the imaging unit. The image processing unit performs an optical distortion correction process for correcting optical distortion of the imaging unit with respect to the imaging data, a shape correction process for correcting geometric distortion, and a specification process for specifying an area of the image recording medium. 7. The image processing apparatus according to claim 4, wherein the image data is subjected to a resolution conversion process for converting a resolution according to the photographing unit and a blurring process for deteriorating sharpness according to the imaging data. The image output device according to claim 1. The image processing unit performs an optical distortion correction process for correcting the optical distortion of the image capturing unit and a specifying process for specifying an area of the image recording medium on the image data, and provides the image data to the image capturing unit. A resolution conversion process for converting a resolution according to the image data, a shape correction process for correcting a geometric distortion according to the image data, and a blur process for deteriorating sharpness according to the image data. The image output device according to any one of claims 4 to 6. The image data is predetermined test image data,
The image processing unit performs an optical distortion correction process for correcting optical distortion of the imaging unit with respect to the imaging data, a shape correction process for correcting geometric distortion, and a specification process for specifying an area of the image recording medium. Alms,
The apparatus according to claim 1, wherein the abnormality detecting unit detects an abnormality in the image by comparing the photographed data after the image processing by the image processing unit with a threshold value set in advance according to the test image data. The image output device according to any one of claims 4 to 6. The image processing means, when outputting a plurality of image recording media on which images are recorded based on an output instruction of the plurality of image recording media, outputs the specified image data from the photographing data photographed when the first image recording medium was outputted. 10. The image processing apparatus according to claim 7, wherein a specific process is performed on image data of the image recording medium to be output thereafter at a specific position when the area of the image recording medium is specified by the processing. 2. The image output device according to claim 1.

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