JP2006076096A - Printing result inspecting apparatus and its method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately carry out quality inspection in a printed result inspecting apparatus which carries out quality inspection of the printing result of a paper that has an original image including a one-dimensional bar code printed on the basis of original image data. <P>SOLUTION: In the printing result inspecting apparatus which carries out quality inspection of the printing result of the paper that has the original image including the one-dimensional bar code printed on the basis of original image data, an image reading adjusting part 32 adjusts, so that a resolution in a lateral direction of bars that constitute the one-dimensional bar code becomes higher than a resolution in a longitudinal direction, reading of the paper printing result at an image reading part 20 which optically reads the printed result of the paper by resolutions different from each other between a main scanning direction and a sub scanning direction. After the adjustment, a collating part 31 acquires inspection image data obtained by reading the printing result of the paper at the image reading part 20 and compares the acquired inspection image data with the original image data corresponding to the data, thereby performing quality inspection of the printing result of the paper. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a printing result inspection apparatus that inspects a printing result on a sheet, and more particularly to a printing result inspection apparatus that inspects a printing result on a sheet on which a one-dimensional barcode is printed.

  2. Description of the Related Art Image forming apparatuses that print images such as characters on paper based on document image data are known. There is a demand to confirm or inspect whether an image printed by the image forming apparatus is printed according to the original document image data.

  Patent Document 1 discloses an inspection method in which a print result is inspected by looking at a match between original image data serving as a basis for printing and inspection image data obtained by optically reading a printed image by a reading device. Yes.

  However, an error may occur with the actually printed image when the reading device reads the image, and the obtained inspection image data may be different from the image data that should originally be obtained. For this reason, the printing result of the sheet that should be determined to be normal by the inspection apparatus may be determined to be abnormal or vice versa.

  Therefore, in order to prevent such a misjudgment, Japanese Patent Application Laid-Open No. H10-228688 discloses a photographed image (corresponding to inspection image data) and a normative image (corresponding to document image data) even when the image reading target paper is misaligned. As a two-dimensional data array, an inspection apparatus is disclosed in which the positional deviation is corrected and the print result is inspected based on the correlation between the captured image and the reference image data array.

  By the way, among the sheets to be inspected as described above, there are sheets on which a one-dimensional barcode is printed based on the document image data. However, because the barcode pitch interval is narrow, the reading device cannot properly read the printing result, and the inspection device mistakenly determines that the printing result of the paper is abnormal, and vice versa. It may be determined to be normal.

Japanese Patent No. 2866339 JP 2002-63566 A

  An object of the present invention is to appropriately perform a quality inspection in a printing result inspection apparatus that performs a quality inspection of a printing result of a sheet on which an original image including a one-dimensional barcode is printed based on the original image data.

  The printing result inspection apparatus according to the present invention includes a reading unit that optically reads a sheet on which a document image including a one-dimensional barcode is printed by the printing apparatus while the sheet is moving on a sheet conveyance path, and the reading unit. The inspection image data acquisition means for acquiring the inspection image data obtained by reading the printing result of the paper, and comparing the acquired inspection image data with the corresponding document image data, An inspection unit that performs quality inspection, and the reading unit is a unit that optically reads a printing result of a sheet with different reading resolutions in the main scanning direction and the sub-scanning direction, and The scanning direction in which the reading resolution of the reading unit is higher and the arrangement direction of the bars constituting the one-dimensional barcode included in the original image coincide with each other. Determining the orientation at the time of printing the image to the print direction instruction means for instructing the printing apparatus to print a document image in the determined direction, comprising: a.

  According to the present invention, the printing direction instructing means is arranged so that the scanning direction in which the reading resolution of the reading means is higher coincides with the arrangement direction of the bars constituting the one-dimensional barcode included in the original image. An orientation for printing an image is determined, and the printing apparatus is instructed to print an original image in the determined orientation. As a result, the resolution in the arrangement direction of the bars constituting the one-dimensional barcode shown in the inspection image data becomes higher, and the thickness of the bar of the one-dimensional barcode shown in the inspection image data, the black bar and the black bar, The error generated between the interval portion of the space between and the thickness or interval portion appearing in the actual print result is reduced, and the error of the inspection result in the inspection means is also reduced.

  The printing result inspection apparatus according to the present invention includes a reading unit that optically reads a sheet on which a document image including a one-dimensional barcode is printed by the printing apparatus while the sheet is moving on a sheet conveyance path, and the reading unit. The inspection image data acquisition means for acquiring the inspection image data obtained by reading the printing result of the paper, and comparing the acquired inspection image data with the corresponding document image data, An inspection unit that performs quality inspection, and the reading unit is a unit that optically reads a printing result of a sheet with different reading resolutions in the main scanning direction and the sub-scanning direction, and The scanning direction in which the reading resolution of the reading means is higher matches the arrangement direction of the bars constituting the one-dimensional barcode included in the original image. Preparative means, characterized in that it comprises a paper rotating means for rotating the sheet conveying direction of the sheet before reading the printed paper of the document image.

  According to the present invention, the paper direction rotating means is arranged so that the scanning direction with the higher reading resolution of the reading means matches the arrangement direction of the bars constituting the one-dimensional barcode included in the original image. The reading unit rotates the paper conveyance direction of the paper before reading the paper on which the document image is printed. As a result, the resolution in the arrangement direction of the bars constituting the one-dimensional barcode shown in the inspection image data becomes higher, and the thickness of the bar of the one-dimensional barcode shown in the inspection image data, the black bar and the black bar, The error generated between the interval portion of the space between and the thickness or interval portion appearing in the actual print result is reduced, and the error of the inspection result in the inspection means is also reduced.

  The printing result inspection apparatus according to the present invention includes a reading unit that optically reads a sheet on which a document image including a one-dimensional barcode is printed by the printing apparatus while the sheet is moving on a sheet conveyance path, and the reading unit. The inspection image data acquisition means for acquiring the inspection image data obtained by reading the printing result of the paper, and comparing the acquired inspection image data with the corresponding document image data, An inspection unit that performs quality inspection, and the reading unit is a unit that optically reads a printing result of a sheet with different resolutions in the main scanning direction and the sub-scanning direction, and The reading means so that the scanning direction with the higher reading resolution of the reading means matches the arrangement direction of the bars constituting the one-dimensional barcode included in the document image. And resolution switching means for switching the reading resolution of the main scanning direction and the sub-scanning direction, characterized in that it comprises a.

  According to the present invention, the resolution switching unit causes the reading direction so that the scanning direction in which the reading resolution of the reading unit is higher coincides with the arrangement direction of the bars constituting the one-dimensional barcode included in the document image. The reading resolution between the main scanning direction and the sub-scanning direction of the means is switched. As a result, the resolution in the arrangement direction of the bars constituting the one-dimensional barcode shown in the inspection image data becomes higher, and the thickness of the bar of the one-dimensional barcode shown in the inspection image data, the black bar and the black bar, The error generated between the interval portion of the space between and the thickness or interval portion appearing in the actual print result is reduced, and the error of the inspection result in the inspection means is also reduced. Furthermore, the direction of the arrangement direction of the bars constituting the one-dimensional barcode printed on the paper is orthogonal to the arrangement direction without depending on the direction of the one-dimensional barcode printed on the paper with respect to the paper conveyance direction. Therefore, depending on the printing direction of the one-dimensional barcode, the longitudinal direction of the paper becomes the paper conveyance direction, and there is no possibility that the number of papers that can be printed within a certain time will be reduced.

  A first embodiment of the present invention (hereinafter referred to as a first embodiment) will be described with reference to the drawings. The first embodiment relates to an image forming apparatus having an inspection function for performing a quality inspection on a printing result of a sheet, and in particular, can appropriately perform a quality inspection even when a one-dimensional barcode is included in a document image printed on a sheet. It is an object of the present invention to provide an image forming apparatus that can be used.

  First, an outline of the image forming apparatus according to the first embodiment will be described. FIG. 1 is a diagram illustrating a schematic configuration of an image forming apparatus according to the first embodiment. Here, the image forming apparatus refers to an apparatus having an image forming function, such as a printer, a copier, a facsimile machine, or a digital multi-function peripheral having at least a printing function. The paper as a printing medium is not only plain paper but also general printing objects such as OHP sheets, cardboard, and postcards.

  The image forming apparatus configured as described above sequentially removes paper from the paper tray 50 based on the document image data, and performs print processing in the print processing unit 10. The document image data is provided from, for example, an external controller connected to the image forming apparatus. The external controller converts the original data provided from the host computer connected to the external controller into, for example, bitmap data or PDL that can be recognized by the image forming apparatus. The original image data is provided to the apparatus.

  Next, the image forming apparatus will be further described with reference to the functional block configuration diagram shown in FIG.

  In the image forming apparatus according to the present exemplary embodiment, the print processing unit 10 that performs a printing process on a sheet taken out from the sheet tray, the image reading unit 20 that optically reads the printing result of the sheet, and the image reading unit 20 read the image. And an inspection unit 30 for inspecting the quality of the printing result for the paper based on the obtained inspection image data.

  As described above, whether or not the printing based on the document image data is normally performed by the inspection unit 30 inspecting the quality of the printing result on the paper based on the inspection image data obtained by sequentially reading the image reading unit 20. The user can grasp this efficiently.

  Further, each part will be described in detail. First, in the print processing unit 10, the control unit 11 is a module that controls the entire image forming apparatus. The printing unit 12 is a mechanism that performs printing on a sheet based on document image data.

  The image reading unit 20 is a mechanism for sequentially reading the printing results of the paper that has been subjected to the printing process by the printing processing unit 10, and the image reading unit 20 reads the printing result of the paper to perform a quality inspection of the printing results. Obtain inspection image data. Specifically, the image reading unit 20 includes an irradiation lamp, an imaging lens, and a CCD line sensor. The reading part of the paper moving on the paper transport path is irradiated with light from the irradiation lamp, the light reflected on the paper is imaged by the imaging lens, and the formed optical images are sequentially taken into the CCD line sensor. The acquired data is binarized to generate inspection image data. Here, the main scanning direction of the image reading unit 20 is the same as the reading direction of the line sensor, and the sub-scanning direction is the same as the paper transport direction.

  Next, in the inspection unit 30, the verification unit 31 is a module that performs verification by comparing the inspection image data with the corresponding document image data, and inspects the print result of the paper. The image reading adjustment unit 32 reads the image so that an error does not occur in the inspection result due to an error generated between the inspection image data obtained by reading the printing result of the paper in the image reading unit 20 and the actual printing result. This module adjusts image reading in the unit 20, which will be described in detail later.

  Here, the quality inspection based on the verification between the inspection image data and the document image data in the verification unit 31 is specifically performed as follows.

  That is, a difference in the total number of pixels is taken between the inspection image data and the document image data that are binarized data, and the quality inspection of the paper is performed based on the difference. For example, when the difference is equal to or larger than the reference value, the collation unit 31 determines that the inspection image data and the document image data do not match and determines that the quality is poor.

  The collation unit 31 may perform a quality inspection based on the overlapping rate between the inspection image data and the document image data. For the overlap rate, for example, it is determined whether or not the values of the respective pixels constituting the inspection image data and the document image data match, and the number of matching pixels (number of matching pixels / number of all pixels) with respect to the total number of pixels is determined. Can be calculated. Then, when the overlap rate is equal to or less than the reference value, the collating unit 31 determines that the inspection image data and the document image data do not match and determines that the quality is poor.

  In the image forming apparatus configured as described above, in the first embodiment, quality inspection is performed on a sheet on which a document image including a one-dimensional barcode 100 as illustrated in FIG. 3 is printed.

  However, if the pitch interval of the one-dimensional barcode printed on the paper is narrow, the image reading unit 20 cannot accurately read the printing result of the paper, and the one-dimensional bar indicated in the obtained inspection image data is displayed. An error may occur in the pitch interval of the code, and the collation unit 31 may erroneously determine that the printing result of the paper is abnormal or vice versa.

  In order to reduce such an error, a method of uniformly increasing the resolution of the image reading unit 20 in the main scanning direction and the sub-scanning direction can be considered. However, when the resolution is increased, the amount of data handled when the image reading unit 20 reads the printing result of the paper increases, and the amount of inspection image data obtained as a result also increases. Therefore, the processing time required for the quality inspection in the inspection unit 30 also increases. However, image forming apparatuses that inspect such print results are strongly demanded to print a large amount of paper at high speed, and the paper conveyance speed in the printing process is often high. Therefore, in the method of simply increasing the resolution in the main scanning direction and the sub-scanning direction of the line sensor constituting the image reading unit 20, the processing time required for the quality inspection in the inspection unit 30 is unnecessarily increased, and printing processing is performed. There is a risk that it will not be possible to meet the demand for higher speeds.

  By the way, in the one-dimensional bar code, the data indicated by the bar code is defined based on the thickness of the black bar constituting the bar code and the space interval between the black bar and the black bar. Therefore, whether or not the one-dimensional barcode printed on the paper has been normally printed may be determined by checking whether the thickness of the black bar or the space between the black bar and the black bar is normal. That is, it is understood that at least the resolution in the arrangement direction of the bars constituting the barcode should be increased in order to eliminate the error in the inspection result of the one-dimensional barcode.

  Based on the above, in the first embodiment, the resolution of the main scanning direction and the sub-scanning direction of the image reading unit 20 is different, the resolution in one direction is set higher, and the resolution in the other direction is lowered. Set to. For example, when the number of pixels of inspection image data that can withstand the inspection processing speed in the inspection unit 30 is 80000 pixels per square inch, this is not allocated evenly in the main / sub-scanning direction resolution, The scanning direction resolution is set to 400 bpi and the sub-scanning direction resolution is set to 200 dpi.

  Note that the sub-scanning direction of the line sensor is the same as the paper conveyance direction, and reading in the sub-scanning direction is reading while conveying the paper. Therefore, blurring due to reading is more likely to occur than in the main scanning direction. Therefore, in order to effectively use the optical resolution, it is preferable to set the resolution in the main scanning direction high and set the resolution in the sub scanning direction low.

  In consideration of the image reading unit 20 configured as described above, the image reading adjustment unit 32 according to the first exemplary embodiment has a scanning direction with a high reading resolution in the image reading unit 20 and an arrangement direction of bars constituting a one-dimensional barcode. Are switched in the same direction so that the print direction of the original image with respect to the paper conveyance direction is switched, and the paper tray to be taken out is switched according to the switched print direction of the original image.

  More specifically, first, the paper is stored in one paper tray provided in the image forming apparatus so that the direction of the paper on the paper transport path in the image forming apparatus is the longitudinal direction, and the paper tray The paper is stored in a different paper tray in the short direction. Then, the image reading adjustment unit 32 acquires document image data from the control unit 11 and determines whether or not a one-dimensional barcode exists in the document image to be printed based on the document image data. As a result of the determination, if a one-dimensional barcode is present, the image reading adjustment unit 32 subsequently specifies the printing direction of the preset document image with respect to the paper transport direction based on the document image data, and further specifies the specified document. The printing direction of the one-dimensional barcode with respect to the printing direction of the image is specified. For example, when the one-dimensional barcode is printed in the horizontal direction with respect to the printing direction of the original image in the case of the paper A in FIG. 3 and in the vertical direction with respect to the printing direction of the original image in the case of the paper B in FIG. Is determined, and the printing direction of the one-dimensional barcode with respect to the printing direction of the document image is specified. Based on the identification result, when the one-dimensional barcode is printed in the horizontal direction, the image reading adjustment unit 32 determines that the printing direction of the original image and the paper tray to be taken out are the same as the preset setting conditions. decide. On the other hand, when the one-dimensional barcode is printed in the vertical direction, the printing direction of the original document image is rotated 90 degrees, and the paper is conveyed in a conveyance direction that is 90 degrees different from the preset paper tray. The setting condition is switched to the paper tray to be sent out on the route. Subsequently, the image reading adjustment unit 32 provides the determined setting condition to the control unit 11, and the control unit 11 designates a paper tray according to the setting condition, and the paper is taken out from the designated paper tray. Thus, the printing unit 12 prints the original image in the printing direction corresponding to the setting condition on the taken-out paper.

  As a result, the image reading unit 20 can always read the image in the bar arrangement direction of the one-dimensional barcode in the scanning direction with high resolution simply by reading the paper on the conveyance path as usual. As a result, the resolution in the bar array direction of the one-dimensional barcode indicated in the inspection image data is always high. Therefore, according to the first embodiment, the thickness portion of the bar of the one-dimensional barcode shown in the inspection image data, the space portion between the black bar and the black bar, and the thickness appearing in the actual print result. Errors that occur between the sheath and the space are reduced, and errors in the inspection results are also reduced.

  The determination of the presence of a one-dimensional barcode based on the document image data in the image reading adjustment unit 32 and the specification of the printing direction of the document image or the one-dimensional barcode may be performed as follows, for example. That is, barcode information indicating the presence / absence of a one-dimensional barcode and the printing direction of the document image or the one-dimensional barcode is added to the document image data in advance. Then, the image reading adjustment unit 32 refers to the barcode information added to the document image data to determine the presence / absence of a one-dimensional barcode, and determines the printing direction of the document image or the one-dimensional barcode. Identify. In addition, the presence / absence of the barcode and the printing direction of the document image or the one-dimensional barcode may be specified directly from the document image using a known image analysis technique.

  Also, in the above, the image reading adjustment unit 32 rotates the printing direction of the original image with respect to the paper conveyance direction by 90 degrees in accordance with the printing direction of the one-dimensional barcode with respect to the paper conveyance direction. An example in which the scanning direction with high resolution and the arrangement direction of the bars constituting the one-dimensional barcode are adjusted to be the same direction has been shown. However, other than that, for example, the adjustment can be performed by the following method. That is, the document image is printed on the paper taken out from the preselected paper tray 50 in the preset printing direction. Then, before the image reading unit 20 reads the printing result of the printed paper, the printed paper is rotated 90 degrees according to the orientation of the one-dimensional barcode with respect to the paper conveyance direction using the paper direction changing device. Even in this method, it is possible to adjust so that the scanning direction with high reading resolution in the image reading unit 20 and the arrangement direction of the bars constituting the one-dimensional barcode are the same direction.

  The sheet direction changing device may be an existing device incorporated in the image forming apparatus. For example, the device described in Japanese Patent Laid-Open No. 05-301659 by the present applicant can be used. Here, Japanese Patent Application Laid-Open No. 05-301659 discloses a paper direction changing device that changes the direction of a conveyed paper. This was to change the direction of the printed paper output from the print engine in a direction suitable for the post-processing when post-processing such as paper folding on the printed paper. It is diverted to change direction. In this case, the paper direction changing device is provided between the print processing unit 10 and the image reading unit 20 of the image forming apparatus of FIG. Then, at the timing when the paper printed by the print processing unit 10 reaches the paper direction changing device, the control unit 11 instructs the paper direction changing device to rotate the direction of the printed paper by 90 degrees. According to such a configuration, the printed paper can be read in an appropriate direction without the user's hand.

  Further, when collation is performed by the collation unit 31, it is necessary to change the resolution of the document image data as well as the inspection image data. Therefore, when the original image data includes a one-dimensional barcode, the collation unit 31 converts the original image data before the collation according to the main / sub-scanning direction resolution in the image reading adjustment unit 32. Perform resolution conversion. Specifically, for example, with respect to original image data having a resolution of 400 dpi in the main and sub-scanning directions, the resolution in the scanning direction corresponding to the horizontal direction of the unified barcode is reduced to 200 dpi. Then, inspection image data and document image data having the same resolution in the main and sub scanning directions are compared and collated. When the main / sub-scanning direction resolutions are determined in advance, the collation unit 31 may acquire document image data whose resolution has been converted in advance from the external controller or the like via the control unit 11.

  As described above, in the first exemplary embodiment, the image reading adjustment unit 32 switches the printing direction of the original image or rotates the printed paper, so that the scanning direction and the one-dimensional barcode with high reading resolution in the image reading unit 20 are displayed. Adjustment is made so that the arrangement direction of the constituent bars is the same. As a result, the horizontal resolution of the one-dimensional barcode shown in the inspection image data is increased, so the thickness of the black bar constituting the one-dimensional barcode or the space between the black bar and the black bar Are read at a higher resolution, and inspection image data is generated. Therefore, according to the first embodiment, the thickness portion of the bar of the one-dimensional barcode shown in the inspection image data, the space portion between the black bar and the black bar, and the thickness appearing in the actual print result. Errors that occur between the sheath and the space are reduced, and errors in the inspection results are also reduced.

  Next, a second embodiment (hereinafter referred to as a second embodiment) of the present invention will be described with reference to the drawings.

  In the first embodiment, the printing direction of the original image is switched or the printed image is printed so that the scanning direction with high reading resolution in the image reading unit 20 and the arrangement direction of the bars constituting the one-dimensional barcode are the same direction. The example of rotating the paper has been described. However, for papers with different sizes in the vertical and horizontal directions, such as standard size paper such as A4 and B5, the same is true when printing with the paper transport direction as the long direction and when printing in the short direction. The number of sheets that can be printed in time is different. In other words, if the long paper direction is the paper transport direction, the number of paper sheets that can be printed at the same time is reduced compared to when the short paper direction is the paper transport direction, which speeds up the printing process. There is a risk that the request cannot be met.

  Therefore, in the second embodiment, the paper transport direction is not switched by switching the printing direction of the original image, or the printed paper is not rotated according to the orientation of the printed one-dimensional barcode with respect to the paper transport direction. The image reading adjustment unit 32 reads the image in the image reading unit 20 by changing the resolution in the main / sub scanning direction of the image reading unit 20 according to the direction of the one-dimensional barcode printed on the paper. adjust.

  FIG. 4 shows a functional block diagram of the second embodiment. For example, when the one-dimensional barcode 100 is printed in the horizontal direction with respect to the paper conveyance direction, as in the case of the paper A shown in FIG. When the resolution is set high and printing is performed in the vertical direction like the paper B, image reading by the image reading unit 20 is adjusted so that the resolution in the sub-scanning direction is set high.

  As a result, the horizontal resolution of the one-dimensional barcode shown in the inspection image data is increased, so the thickness of the black bar constituting the one-dimensional barcode or the space between the black bar and the black bar Are read at a higher resolution, and inspection image data is generated. Therefore, according to the second embodiment, as in the first embodiment, the bar thickness portion of the one-dimensional bar code indicated in the inspection image data, the space portion between the black bar and the black bar, and the actual print result. The error that occurs between the thickness and the interval portion appearing in (2) is reduced, and the error in the inspection result is also reduced. Furthermore, in the second embodiment, since the paper transport direction can be fixed, the number of sheets that can be printed within a certain time may be reduced by setting the paper longitudinal direction as the paper transport direction as in the first embodiment. There is no.

  Specifically, the resolution of the image reading unit 20 in the main and sub-scanning directions may be changed as follows. First, the image reading unit 20 capable of reading in the main scanning direction of 400 dpi is driven with a line sync (synchronization signal (one line cycle)) in the sub-scanning direction of 200 dpi so that an appropriate S / N ratio can be obtained. Configure the scanning system and optical system. Further, the line sensor has a one-pixel reading mode for reading out charge for each pixel and a two-pixel reading mode for reading out the combined signal charges of two adjacent pixels. In the second embodiment, these two modes are used. Is switched to change the resolution in the main and sub-scanning directions.

  Here, the description of the one-pixel readout mode is omitted for the readout process by the line sensor that is normally performed, and the two-pixel readout mode will be further described with reference to FIG.

  In FIG. 6, initially, the potential of the horizontal transfer electrode corresponding to the odd pixel is set to the high level, and the potential of the horizontal transfer electrode corresponding to the even pixel is set to the low level (S101). Next, the first shift gate corresponding to the odd pixel is set to the high level to shift and transfer the signal charge of the odd pixel from the photosensitive pixel column to the horizontal transfer electrode (S102). Further, by inverting the phase of the applied voltage of the horizontal transfer electrode, each signal charge is sent to the transfer electrode corresponding to the adjacent even pixel example. At the same time, the second shift gate corresponding to the even-numbered pixel column is set to High level, and the signal charge of the even-numbered pixel column is transferred to the corresponding horizontal transfer electrode (S103). Thereby, the outputs of two adjacent pixels can be synthesized. Thereafter, the signal charges are sequentially transferred in the horizontal direction while sequentially inverting the phase of the drive voltage applied to the horizontal transfer electrode (S104). At this time, the frequency of the line sync in the two-pixel readout mode is set to twice that in the one-pixel readout mode. Thus, by doubling the line sync frequency, the resolution in the sub-scanning direction is doubled to 400 dpi. At this time, although the exposure time is halved, the S / N ratio is maintained because two adjacent pixels are combined as described above. Further, by combining the signal charges of the two pixels, the resolution in the main scanning direction is halved to 200 dpi.

  In the line sensor configured as described above, when the one-dimensional barcode 100 is printed in the horizontal direction with respect to the paper transport direction as in the paper A of FIG. 5, the reading mode of the line sensor is set to one image. As a reading mode, reading is performed with a high resolution in the main scanning direction. On the other hand, when the one-dimensional barcode 100 is printed in the vertical direction with respect to the paper transport direction as in the paper B of FIG. 4, the line sensor reading mode is set to the two-image reading mode and the sub-scanning direction is set. Set the resolution higher and scan. As a result, regardless of the printing direction of the one-dimensional barcode, the thickness of the black bar and the space between the black and black bars can be read with higher resolution. It is.

  Therefore, according to the second embodiment, as in the first embodiment, the bar thickness portion of the one-dimensional bar code indicated in the inspection image data, the space portion between the black bar and the black bar, and the actual print result. The error that occurs between the thickness and the interval portion appearing in (2) is reduced, and the error in the inspection result is also reduced. Furthermore, in the second embodiment, the resolution in the arrangement direction of the bars constituting the one-dimensional barcode printed on the paper is not dependent on the orientation of the one-dimensional barcode printed on the paper with respect to the paper conveyance direction. Since the resolution can be higher than the direction orthogonal to the direction, the longitudinal direction of the sheet becomes the sheet conveying direction according to the printing direction of the one-dimensional barcode as in the first embodiment, and the number of sheets that can be printed within a certain time is determined. There is no risk of a decrease.

  In the second embodiment, an example in which the combination of the resolutions in the main and sub scanning directions of the image reading unit 20 is two types and switching between 400 dpi and 200 dpi is shown, but the resolution is not limited to these two types, and other types Switching may be performed depending on the combination of resolutions, or three or more combinations of resolutions may be prepared, and switching may be performed each time depending on the original image to be read. In addition, in order to prevent blur in the sub-scanning direction by reading an image with a line sensor while conveying a sheet, if the original image does not include a one-dimensional barcode, the image reading adjustment in the second embodiment The unit 32 may be adjusted so that the resolution in the sub-scanning direction is set higher. This is preferable because the characteristics of the optical system (lens) constituting the line sensor are generally superior in resolving ability in the main scanning direction compared to resolving ability in the sub-scanning direction.

1 is a diagram illustrating a schematic configuration of an image forming apparatus according to Embodiments 1 and 2. FIG. 2 is a functional block diagram of an image forming apparatus according to Embodiment 1. FIG. It is a figure which shows an example of the paper on which the original image containing a one-dimensional barcode was printed. 6 is a functional block diagram of an image forming apparatus according to Embodiment 2. FIG. It is a figure which shows an example of the paper on which the original image containing a one-dimensional barcode was printed. FIG. 10 is a diagram illustrating a pixel reading procedure in a two-pixel reading mode of the line sensor according to the second embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Print processing part, 11 Control part, 12 Printing part, 20 Image reading part, 30 Inspection part, 31 Collation part, 32 Image reading adjustment part, 50 Paper tray.

Claims (7)

Reading means for optically reading a sheet on which a document image including a one-dimensional barcode is printed by a printing apparatus while the sheet is moving on a sheet conveyance path;
Inspection image data acquisition means for acquiring inspection image data obtained by the reading means reading the printing result of the paper;
An inspection means for performing a quality inspection of the printing result of the paper by comparing the acquired inspection image data and the corresponding document image data;
In a printing result inspection apparatus comprising:
The reading unit is a unit that optically reads a printing result of a sheet with different reading resolutions in the main scanning direction and the sub-scanning direction,
Further, the scanning direction of the reading means having a higher reading resolution is determined so that the orientation of the original image is printed so that the arrangement direction of the bars constituting the one-dimensional barcode included in the original image coincides, A print direction instruction means for instructing the printing apparatus to print a document image in the determined orientation;
A printing result inspection apparatus comprising: Reading means for optically reading a sheet on which a document image including a one-dimensional barcode is printed by a printing apparatus while the sheet is moving on a sheet conveyance path;
Inspection image data acquisition means for acquiring inspection image data obtained by the reading means reading the printing result of the paper;
An inspection means for performing a quality inspection of the printing result of the paper by comparing the acquired inspection image data and the corresponding document image data;
In a printing result inspection apparatus comprising:
The reading unit is a unit that optically reads a printing result of a sheet with different reading resolutions in the main scanning direction and the sub-scanning direction,
Further, the sheet on which the document image is printed is read so that the scanning direction with the higher reading resolution of the reading unit coincides with the arrangement direction of the bars constituting the one-dimensional barcode included in the document image. Paper direction rotating means for rotating the paper transport direction of the paper before reading
A printing result inspection apparatus comprising: Reading means for optically reading a sheet on which a document image including a one-dimensional barcode is printed by a printing apparatus while the sheet is moving on a sheet conveyance path;
Inspection image data acquisition means for acquiring inspection image data obtained by the reading means reading the printing result of the paper;
An inspection means for performing a quality inspection of the printing result of the paper by comparing the acquired inspection image data and the corresponding document image data;
In a printing result inspection apparatus comprising:
The reading unit is a unit that optically reads the printing result of the paper with different resolutions in the main scanning direction and the sub-scanning direction,
Further, the main scanning direction and the sub-scanning direction of the reading unit are set so that the scanning direction with the higher reading resolution of the reading unit matches the arrangement direction of the bars constituting the one-dimensional barcode included in the original image. Resolution switching means for switching the reading resolution with
A printing result inspection apparatus comprising: In the printing result inspection apparatus according to claim 3,
The reading unit includes a line sensor installed in a direction orthogonal to the paper conveyance direction, and the reading resolution in the main scanning direction of the reading unit is determined by the reading resolution of the line sensor, and the sub-scanning of the reading unit The direction reading resolution is determined by the line reading cycle of the line sensor.
The printing result inspection apparatus, wherein the resolution switching unit switches the reading resolution between the main scanning direction and the sub-scanning direction of the reading unit by switching between the reading resolution of the line sensor and a line reading repetition cycle. A reading step of optically reading a sheet on which a document image including a one-dimensional barcode is printed by a printing apparatus while the sheet moves on a sheet conveyance path;
An inspection image data acquisition step of acquiring inspection image data obtained by reading the printing result of the paper in the reading step;
An inspection process for performing a quality inspection of the printing result of the paper by comparing the acquired inspection image data and the corresponding document image data;
In the printing result inspection method including
The reading step is a step of optically reading the printing result of the paper with different reading resolutions in the main scanning direction and the sub-scanning direction,
Further, the orientation at the time of printing the original image is determined so that the scanning direction with the higher reading resolution in the reading step matches the arrangement direction of the bars constituting the one-dimensional barcode included in the original image. A printing direction instruction step for instructing the printing apparatus to print a document image in the determined orientation;
A printing result inspection method including: A reading step of optically reading a sheet on which a document image including a one-dimensional barcode is printed by a printing apparatus while the sheet moves on a sheet conveyance path;
An inspection image data acquisition step of acquiring inspection image data obtained by reading the printing result of the paper in the reading step;
An inspection process for performing a quality inspection of the printing result of the paper by comparing the acquired inspection image data and the corresponding document image data;
In the printing result inspection method including
The reading step is a step of optically reading the printing result of the paper with different reading resolutions in the main scanning direction and the sub-scanning direction,
Further, the original image is printed in the reading step so that the scanning direction with the higher reading resolution in the reading step matches the arrangement direction of the bars constituting the one-dimensional barcode included in the original image. A paper direction rotation step for rotating the paper transport direction of the paper before reading the paper;
A printing result inspection method including: A reading step of optically reading a sheet on which a document image including a one-dimensional barcode is printed by a printing apparatus while the sheet moves on a sheet conveyance path;
An inspection image data acquisition step of acquiring inspection image data obtained by reading the printing result of the paper in the reading step;
An inspection process for performing a quality inspection of the printing result of the paper by comparing the acquired inspection image data and the corresponding document image data;
In the print result inspection direction including
The reading step is a step of optically reading the printing result of the paper with different resolutions in the main scanning direction and the sub-scanning direction,
Further, the main scanning direction and the sub-scanning in the reading step are set so that the scanning direction with the higher reading resolution in the reading step matches the arrangement direction of the bars constituting the one-dimensional barcode included in the document image. A resolution switching step of switching the reading resolution with the direction;
A printing result inspection method including:

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