JP4692168B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus, and more particularly to an electrophotographic image forming apparatus that forms a toner image on a surface of a photoreceptor and transfers the image to a recording medium to form an image including a barcode.

  With the recent expansion of fee collection services such as gas, electricity and tickets provided at convenience stores, the opportunity to output barcodes using an electrophotographic printer capable of high-speed recording has greatly increased. ing.

  In general, a barcode has a black or color thin line called “BAR” and a paper color (background color) called “SPACE”, and includes “UPC” (USA, Canada), “EAN” (Europe), It is standardized in detail by “JAN” (Japan). In recent years, in addition to the currently popular JAN code and standard logistics code (ITF) information, “EAN-128”, a format that displays more information such as logistics information and commercial transaction information in a small print space, has increased. There is also a trend, and the transfer from JAN code (13 digits x 3 to 4 stages) to EAN-128 bar code (44 digits x 1 stage) is also progressing in transfer forms used when collecting fees at convenience stores. It is out.

  For this transfer paper, it is desired to reduce the size of the barcode. For example, in the case of a JAN code, the size of a bar code becomes large even with a relatively small amount of information, so that the advertising space of a company becomes small or the transfer paper itself becomes large and becomes unsuitable for mailing. Therefore, among the EAN-128 barcodes, a smaller module having a narrower BAR and SPACE is often used. However, the EAN-128 barcode printed on transfer paper, etc., is defined as 44 digits (44 digits fixed length), and the number of digits compared to 13 digits (standard type) or 8 digits (shortened type) of JAN code. Therefore, especially in a small module, in order to prevent the bar code reading rate (the ratio that can be read by a bar code reader with one or two scans) from decreasing, high-density and high-definition BAR / A high resolution capable of accurately reproducing SPACE is required, and image quality equivalent to that of a printing press is required.

In the case of a printing press, the image quality level is high, but it is not possible to handle printing of data that changes for each sheet, such as barcode printing on the transfer sheet. For this reason, an electrophotographic printer or an ink jet printer is used for barcode printing of such transfer paper. In order to increase the barcode reading rate in the printer (barcode printer), it is written together with the barcode. When a number is unnecessary, a technique for printing a bar code (BAR) for a long time using the space without printing the number is disclosed (for example, see Patent Document 1).
Japanese Patent Publication No. 6-4345

  However, in the case of an EAN-128 barcode, especially a module of its thin bar, the main causes of reading errors are blurring of the outline (edge) due to BAR blurring, and SPACE collapse due to BAR thickening, As in the technique of Patent Document 1 described above, a simple improvement effect cannot be obtained by simply extending the BAR. For example, as in this technique, even if the barcode is made longer by the size of the printing space occupied by the numbers, it is extended by about 30%, and the reading rate is improved only by about 10%.

  In addition, when printing with low image density is continuously performed, the toner is easily stirred in the developing unit of the printer for a longer time than usual, and the toner is easily crushed. Compared with image quality. In general images, even this level of deterioration (decrease in image quality) is not a problem, but the quality of the barcode is fatal, and in particular, the reading rate of the EAN-128 barcode is greatly reduced.

  On the other hand, with the recent trend toward colorization, the number of color barcodes using corporate colors has increased, and the promotion of resource saving (recycling) against the background of environmental problems has led to the use of recycled paper with low whiteness. Bar code printing is also increasing. However, in these cases, an increase in reading error is a problem because it causes a decrease in contrast between the barcode color and the paper color.

  In view of the above-described facts, an object of the present invention is to provide an image forming apparatus capable of printing a barcode in which the occurrence of a reading error by a barcode reader is suppressed and the reading rate is improved.

In order to achieve the above object, an invention according to claim 1 is an image forming apparatus for forming a toner image on a surface of a photosensitive member and transferring the toner image to a recording medium to form an image including a barcode. In the non-image area where the toner image is not formed, a toner patch is formed corresponding to the barcode toner image, and the density detection means for detecting the density of the toner patch, and the density detection means detected by the density detection means And determining means for determining the quality of the bar code based on the density of the toner patch .

In the present invention, the barcode is printed by forming a toner patch corresponding to the barcode toner image in a non-image area where the toner image is not formed on the surface of the photosensitive member by printing the barcode by the image forming apparatus. It is always formed with new toner that is not damaged in the developing unit. As a result, for example, when the BAR blurs and the outline becomes unclear, when the BAR is thick and the EAN-128 barcode is easily collapsed, or when the print with a low image density is continuously printed in large quantities. However, it is possible to stabilize the barcode density without fluctuation, and to suppress deterioration in image quality. Therefore, with this barcode, the occurrence of reading errors by the barcode reader can be suppressed and the reading rate can be improved.
Also, in the present invention, the determination means, for example, when the density of the toner patch detected by the density detection means is within a predetermined range, the barcode toner image is also properly corrected at the predetermined density. It is determined that it is formed, and image formation is performed. Also, if the density of the toner patch detected by the density detection means is outside the predetermined range, it is determined that a density error has occurred in the barcode toner image, for example, image formation is stopped or an error is detected. Output log. Thereby, the quality of the barcode can be constantly confirmed during printing, and quality control becomes easy.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the number of times the toner patch is formed is changed according to a standard of the barcode.

  In the present invention, for example, a JAN code or a Code 39 barcode that is advantageous for occurrence of a reading error due to a decrease in image quality due to a small number of digits and a relatively low density of BAR / SPACE. The desired image quality is ensured while reducing the number of toner patches formed on the non-image area of the photoconductor to reduce the toner consumption. In addition, because of the large number of digits and the relatively high density of BAR / SPACE, the EAN-128 barcode or information pattern, which is disadvantageous to the occurrence of reading errors accompanying image quality degradation, is two-dimensionalized. Due to its complexity, the number of toner patches formed in the non-image area of the photoconductor is increased for QR codes (two-dimensional codes) that are disadvantageous to the occurrence of reading errors due to deterioration in image quality. Thus, priority is given to ensuring good image quality by always forming barcodes with new toner.

  In this way, by changing the number of times the toner patches are formed on the non-image area of the photoconductor according to the bar code standard, the toner consumption can be reduced and the running cost of the image forming apparatus can be reduced. A good barcode can be printed.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the density of the toner patch is changed according to a standard of the barcode.

  In the present invention, for example, for a JAN code or a Code 39 bar code that is advantageous for occurrence of a reading error due to a decrease in image quality, the density of a toner patch formed in a non-image area of the photoreceptor is suppressed to a low level. The desired image quality is ensured while suppressing toner consumption. Also, for EAN-128 barcodes and QR codes, which are disadvantageous to the occurrence of reading errors due to image quality degradation, the density of toner patches formed in the non-image area of the photoreceptor is increased. Priority is given to ensuring good image quality by forming codes with newer toner.

  As described above, by changing the density of the toner patch formed on the non-image area of the photoconductor according to the barcode standard, the toner consumption can be suppressed and the running cost of the image forming apparatus can be suppressed. A good barcode can be printed.

  According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the size of the toner patch is changed according to a standard of the barcode. It is said.

  In the present invention, for example, the size (area) of the toner patch formed in the non-image area of the photosensitive member for a JAN code or a Code 39 barcode that is advantageous for occurrence of a reading error due to a decrease in image quality. The desired image quality is ensured while reducing the toner consumption to reduce the toner consumption. Also, for EAN-128 barcodes and QR codes, which are disadvantageous to the occurrence of reading errors due to a decrease in image quality, the size of the toner patch formed in the non-image area of the photoreceptor is increased, Priority is given to ensuring good image quality by forming barcodes with newer toner.

  In this way, by changing the size of the toner patch formed on the non-image area of the photoconductor according to the barcode standard, the toner consumption can be suppressed and the running cost of the image forming apparatus can be reduced. A bar code with good quality can be printed.

A fifth aspect of the present invention is the image forming apparatus according to any one of the first to fourth aspects, further comprising a plurality of image forming means for forming images of different colors, wherein the color of the barcode is recorded in the recording medium. It is characterized in that it is a complementary color of the background color at the barcode forming position in the medium, or a color having the highest contrast with respect to the background color among the hues that can be formed.

  In the present invention, when printing a color barcode or printing a barcode on recycled paper with low whiteness, for example, when a plurality of image forming means corresponding to the formation of a full color image are provided, The color is a complementary color of the background color of the barcode forming position on the recording medium. In addition, when a plurality of image forming units corresponding to specific colors such as red and blue are provided, and the color is selected from the plurality of colors, the barcode color is set in the formable hue in the recording medium. A color having the highest contrast with respect to the background color at the barcode forming position is selected.

  As a result, the occurrence of barcode reading errors caused by a decrease in contrast between the barcode color and the background color (paper color) can be suppressed, and the reading rate can be improved.

  According to the image forming apparatus of the present invention, it is possible to print a bar code that suppresses the occurrence of a reading error by the bar code reader and improves the reading rate.

  An image forming apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, an image forming apparatus 10 according to the present embodiment is a color laser printer using an electrophotographic method, and includes four colors Y (yellow), M (magenta), C (cyan), and K (black). It includes print engines 36Y, 36M, 36C, and 36K that form color toner images, and supports full-color printing.

  The image forming apparatus 10 is provided with a display unit 62 such as a liquid crystal display panel on the upper surface, and a paper feed cassette in which preprinted paper (transfer paper) P that is a recording medium of the present embodiment is loaded. 20, an image forming unit 14 for forming a desired image on the preprinted paper P, a fixing device 12 for fixing the image formed on the preprinted paper P, and a transport for transporting the preprinted paper P A paper conveyance system provided with the roll 18 and a control unit 80 for controlling the operation of the entire image forming apparatus 10 are provided.

  In this image forming apparatus 10, first, a toner image is formed on the photosensitive belt 16 by the image forming unit 14, and this toner image is transported from the paper feed cassette 20 to the transfer unit 22 by the transport roll 18. Transferred to P. Then, the preprint paper P to which the toner image has been transferred is pressurized and heated by the fixing device 12 on the downstream side in the transport direction of the transfer unit 22 to fix the toner image on the preprint paper P. 26 is discharged. When images are formed on both the front and back sides of the preprinted paper P, the preprinted paper P with the toner image fixed on the front and back surfaces is switched by switching the transport path downstream in the transport direction of the fixing device 12. It is conveyed to the back surface conveyance path 28 for reversing. Then, the preprinted paper P with the front and back reversed is transported to the upstream side in the transport direction of the transfer unit 22 by the transport belt 29, transported again to the transfer unit 22 by the transport roll 18, and the toner image from the photoreceptor belt 16 to the back surface. Is transcribed. Then, the preprinted paper P passes through the fixing device 12, the toner image is fixed on the back surface, and is discharged to the stacker 26 by the paper discharge roll 24.

  The image forming unit 14 includes a belt driving device 60. The belt driving device 60 includes a photosensitive belt 16 that is an endless belt, a driving roll 32 on which the photosensitive belt 16 is rotatably stretched, and a driven roll 34. The drive roll 32 is disposed along the conveyance path 30 extending in the up-down direction, the driven roll 34 is disposed in the horizontal direction of the drive roll 32, and the photosensitive belt 16 is stretched in the horizontal direction. ing.

  In the image forming unit 14, print engines 36Y, 36M, 36C, and 36K that respectively form Y, M, C, and K toner images on the surface of the photoreceptor belt 16 are provided along the lower flat surface 16B. It is arranged. Each print engine 36 includes a charger 37, an exposure head 38, and a developing device 39 that are sequentially arranged in the rotation direction of the photosensitive belt 16 (the direction of arrow A in the figure). The charger 37 uniformly charges the photosensitive belt 16 with a charging corotron, a charging roll, or the like. Further, the exposure head 38 exposes the charged surface of the photosensitive belt 16 with an LED array, an optical scanning device (Raster Optical Scanner), or the like to form an electrostatic latent image on the photosensitive belt 16 based on image data. . The developing device 39 contains a one-component developer made of toner or a two-component developer made of toner or carrier, and transports the developer to the developing roll 39A while stirring the developer in the developing device 39. The developing device 39 applies a developing bias to the developing roll 39A, and moves the toner from the developing roll 39A onto the electrostatic latent image on the photosensitive belt 16. As a result, the electrostatic latent image on the photoreceptor belt 16 is visualized with toner. Here, the Y, M, and C color toners are superimposed on the same dot to form a full color, and the K (black) toner is not superimposed on the same dot, and each dot is a full color and black toner. It is formed.

  A density sensor 64 for detecting the density of a toner patch formed on the photosensitive belt 16 is provided at the most downstream portion of the lower flat surface 16B on the lower side of the photosensitive belt 16, and the density sensor 64 is As shown in FIG. 4, a plurality (four in this embodiment) are arranged along the width direction (arrow X direction) of the photosensitive belt 16 at a predetermined interval.

  Further, a transfer corotron 42 is disposed facing the photosensitive belt 16 with the conveyance path interposed therebetween. The transfer corotron 42 discharges toward the back surface of the preprinted paper P and gives a charge opposite in polarity to the toner charge in a non-contact manner on the back surface of the preprinted paper P to preprint the toner image on the photoreceptor belt 16. Transfer to paper P.

  A cleaning mechanism 44 including a cleaning blade 100 and a blade bracket for holding the cleaning blade 100 is disposed facing the flat surface 16A on the upper side of the photosensitive belt 16. The cleaning mechanism 44 removes untransferred residual toner remaining on the photosensitive belt 16 without being transferred to the preprinted paper P by the transfer unit 22 from the photosensitive belt 16.

  The fixing device 12 disposed on the downstream side in the transport direction of the transfer unit 22 is in contact with the heat roll 46 that rotates in contact with the transfer surface of the preprint paper P, and press-contacts the heat roll 46 between the preprint paper P. The pressure roll 48 rotates in contact with the back surface of the preprinted paper P, and a fixing nip N is formed by the heat roll 46 and the pressure roll 48. A heater lamp 50 such as a halogen lamp is disposed inside the heat roll 46, and the surface of the heat roll 46 is heated. Therefore, when the preprinted paper P to which the toner image is transferred passes through the fixing nip N, the preprinted paper P is heated and pressurized, and the toner on the preprinted paper P is melted to form the preprinted paper P. It is fixed.

  Here, the fixing device 12 is provided with a release agent supply device 13. The release agent supply device 13 includes a donor roll 52 that is in contact with the surface of the heat roll 46, a tank 54 that stores a release agent such as silicon oil, a sponge and the like in the release roll in the donor roll 52 and the tank 54. And a metering roll 56 in contact with each other through the absorber.

  A metering blade (not shown) is in contact with the surface of the metering roll 56. The metalling blade contacts the surface of the metalling roll 56 with a predetermined pressure, and regulates (measures) the release agent on the surface of the metalling roll 56 to a predetermined thickness with micron order accuracy.

  A release agent having a predetermined thickness on the surface of the metalling roll 56 is conveyed to the surface of the heat roll 46 by the donor roll 52, and a layer of the release agent having a predetermined thickness is formed on the surface of the heat roll 46. Is formed. As a result, the releasability of the toner on the preprinted paper P from the surface of the heat roll 46 in the fixing nip N is improved, so that fixing failure and toner fixing offset can be prevented.

  Further, a purge tray 27 is disposed on the downstream side of the fixing device 12 in the conveyance direction, and some trouble occurs during the conveyance, and an appropriate printing process cannot be performed. Ejected and loaded.

  As shown in FIG. 2, the control unit 80 drives the display unit 62, the image forming unit 14, the fixing device 12, the belt driving device 60 that drives the photosensitive belt 16, and the paper conveyance system. A transport system driving unit 78 is connected. The control unit 80 sends control signals to these units to control the overall operation of the image forming apparatus 10.

  In such an electrophotographic image forming apparatus 10, when barcodes are printed on the preprinted paper P, the image density (the density of the visualized real image with respect to the entire image area) is particularly 2% or less. When low prints are continuously printed, the toner is agitated in the developing unit 39 for a longer time than usual and tends to be crushed, and the image quality is deteriorated as compared with the new toner carried into the developing unit 39 later. In general images, even this level of image quality degradation does not cause a problem, but the quality of the barcode is fatal. In particular, in the EAN-128 barcode, the occurrence of reading errors by the barcode reader increases. .

  FIGS. 3A to 3C show an example of a small EAN-128 barcode (44 digits) printed on the preprinted paper P of the present embodiment and having a thin BAR and SPACE module. In FIG. 3, the EAN-128 barcode 70A shown in FIG. 3A is an example in which the ratio of BAR is small (the ratio of SPACE is large) in the entire barcode, and EAN-128 shown in FIG. The barcode 70C is an example in which the proportion of BAR is large in the entire barcode (the proportion of SPACE is small), and the EAN-128 barcode 70B shown in (B) has the proportion of BAR in the whole barcode. This is an intermediate example between (A) and (C).

  In such EAN-128 barcodes 70A to 70C, as described above, when a print with a low image density is continuously printed, due to toner deterioration, the BAR blurs and the outline becomes unclear, or the BAR becomes thick. As a result, the SPACE is easily crushed, and the occurrence of reading errors by the barcode reader is likely to increase.

  Therefore, a method for printing a barcode with high image quality that can suppress occurrence of a reading error will be described below.

(First embodiment)
In barcode printing by the image forming apparatus 10 according to the present embodiment, the control unit 80 controls the image forming unit 14 and, as shown in FIG. 4, a predetermined position (two points) of the image area IA on the photosensitive belt 16. A barcode toner image 72 is formed in a range corresponding to the preprinted paper P indicated by a chain line, and further, the formation position of the toner image 72 is grasped by image processing in the control unit 80, and the toner image 72 A rectangular toner patch 80 is formed in a non-image area (inter-image) NA where a toner image between the image areas IA is not formed. The toner patch 80 is formed at substantially the same position as the toner image 72 in the rotation direction of the photosensitive belt 16 (arrow A direction / Y direction), and the width dimension (X direction dimension) is the width of the toner image 72. Make it approximately the same or larger than the dimensions.

  As described above, in this embodiment, the barcode toner image 72 formed on the photosensitive belt 16 is always formed with new toner that is not damaged in the developing device 39, and the EAN-128 bar. Even when a code is printed or when a large number of prints having a low image density are continuously printed, the density of the barcode is stable without fluctuation, and the deterioration of the image quality can be suppressed. Therefore, if the barcode is printed on the preprinted paper P by the image forming apparatus 10, the occurrence of a reading error by the barcode reader is suppressed and the reading rate is improved.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the second embodiment, the amount of toner consumption that increases with the formation of the toner patch described in the first embodiment is suppressed, and barcode quality control is performed using the toner patch. The method will be described with reference to the flowchart of FIG. 5 showing the printing operation (image forming operation) of the image forming apparatus 10. Here, the image forming apparatus 10 will be described assuming that it supports four types of barcode printing: JAN code, Code 39 barcode, QR code (two-dimensional code), and EAN-128 barcode.

  When a print job is input from a client such as a PC connected to the network to the control unit 80 of the image forming apparatus 10 (step 100), the control unit 80 develops an image from the print job data (step 102). Conversion processing to barcode font is executed (step 104).

  Subsequently, the barcode printing position (XY position) is obtained from the print job data (step 106), and barcode standard determination processing is executed (steps 108 to 114).

  In this bar code standard determination process, if it is determined that the code is a JAN code (affirmative determination in step 108), the toner patch formed in the non-image area NA on the photosensitive belt 16 described in the first embodiment. 78 is formed three times for seven prints (step 116). Specifically, toner patches 78 are formed three times, for example, every other non-image area NA provided between the seven image areas IA corresponding to seven prints.

  Furthermore, when the density of the toner patch 78 is detected by the density sensor 64 (see FIG. 4) and the density of the toner patch 78 is within a predetermined range (affirmative determination in step 124), the bar It is determined that the code toner image 72 is also normally formed at a predetermined density, and the same operation is repeated until the printing of all the prints included in the print job is completed (No determination in step 126). When all the prints are finished, the printing operation for the print job is finished (step 130).

  Further, as a specific density determination method using the above density sensor 64, for example, the voltage level output from the density sensor 64 is set in a range of 0 to 5 V according to the detected density, and the voltage level without the toner patch is set. When the voltage level is set to drop to 1.2 to 1.5 V when a toner patch having a predetermined density (normal density) is detected at 4.5 V, the voltage level range of the normal density is A margin is set to 1.35 ± 0.5V. Therefore, if the voltage level output from the density sensor 64 that detects the density of the toner patch 78 is 1.35 ± 0.5 V, the toner patch 78 and the barcode toner image 72 are formed at a normal density. It is determined that

  On the other hand, if the density of the toner patch 78 fluctuates due to leakage of the charger 37 or failure of the developing device 39, and the density determination described above determines that the density of the toner patch 78 is outside the predetermined range ( When the voltage level output from the density sensor 64 exceeds the range of 1.35 ± 0.5 V, the toner patch 78 and the barcode toner image 72 are normal. It is determined that the density is not formed, and printing for the job is stopped (step 128), or the abnormal page is left in the control unit 80 as an error log.

  In the barcode standard determination process, if it is determined that the barcode is a Code 39 barcode (affirmative determination is made in step 110 after a negative determination in step 108), the barcode toner image 72 is printed on seven sheets. On the other hand, it is formed four times (step 118). The same operation is repeated for the Code 39 bar code until the printing of all the prints included in the print job is completed while executing the density determination of the toner patch 78 as in the JAN code described above.

  Further, in the barcode standard determination process, if it is determined to be a QR code (affirmative determination in step 112 after negative determination in step 110), the barcode toner image 72 is printed with respect to seven prints. 6 times (step 120). Specifically, the toner images 72 are formed in all of the six non-image areas NA provided between the seven image areas IA corresponding to the seven prints. Similarly, for this QR code, the same operation is repeated until the printing of all the prints included in the print job is completed while executing the density determination of the toner patch 78.

  In the barcode standard determination process described above, if none of the JAN code, Code 39 barcode, or QR code is applicable, it is determined to be an EAN-128 barcode (step 114 after a negative determination in step 112). In this case, similarly to the QR code, the barcode toner image 72 is formed six times for seven prints (step 122). Similarly, for the EAN-128 barcode, the same operation is repeated until the printing of all the prints included in the print job is completed while determining the density of the toner patch 78.

  As described above, according to the present embodiment, since the number of digits is small and the BAR / SPACE is relatively low density, the JAN code or the Code 39 bar code that is advantageous for the occurrence of a reading error accompanying the deterioration of the image quality is used. As a result, the number of toner patches 78 formed in the non-image area NA on the photoreceptor belt 16 is reduced to reduce the amount of toner consumed, while ensuring a desired image quality, and the information pattern is two-dimensionalized. Due to the complexity, QR codes that are disadvantageous to the occurrence of reading errors due to deterioration in image quality, a large number of digits, and relatively high density of BAR / SPACE, reading due to deterioration in image quality For EAN-128 barcodes that are disadvantageous to the occurrence of errors, the number of toner patches 78 formed in the non-image area NA on the photosensitive belt 16 is increased. Since the barcode is always formed with new toner and priority is given to securing good image quality, the running cost of the image forming apparatus 10 can be reduced while reducing the toner consumption, and a barcode with good quality can be obtained. Can be printed. Furthermore, the quality control is facilitated by constantly checking the quality of the barcode during printing by monitoring the density of the toner patch 78.

(Third embodiment)
Next, a third embodiment of the present invention will be described. The third embodiment is a modification of the above-described second embodiment, and will be described with reference to the flowchart of FIG. 6 showing the printing operation.

  In steps 140 to 154 of the flowchart shown in FIG. 6, the same operations as those in steps 100 to 114 of the flowchart shown in FIG. 5 described in the second embodiment are performed.

  If the barcode standard to be printed is JAN code (affirmative determination in step 148), as shown in FIG. 7A, the photosensitive belt 16 is made to correspond to the toner image 74 of the JAN code. A low density toner patch 78A set to a predetermined density is formed in the upper non-image area NA (step 156).

  In the case of a Code 39 barcode (affirmative determination in Step 150 after a negative determination in Step 148), as shown in FIG. 7B, the photosensitive belt is associated with the toner image 76 of the Code 39 barcode. A medium density toner patch 78B having a higher density than the toner patch 78A is formed in the non-image area NA on the image 16 (step 158).

  In the case of a QR code (positive determination in step 152 after a negative determination in step 150), or in the case of an EAN-128 barcode (step 154 after a negative determination in step 152), the toner of the QR code In correspondence with the image, or as shown in FIG. 7C, in correspondence with the toner image 72 of the EAN-128 barcode, the non-image area NA on the photosensitive belt 16 has a density higher than that of the toner patch 78B. The toner patch 78C having a high density is formed (step 160/162).

  Even when the density of the toner patch 78 is changed as described above, by setting the output voltage level of the density sensor 64 within a predetermined range corresponding to the density, that is, to the high density toner patch 78C. For the low-concentration toner patch 78A, the voltage level standard is increased, and for the low-density toner patch 78A, the voltage level standard is decreased. As in the second embodiment, the toner patches 78A, 78B, and 78C having different densities are used. The density determination (quality control) of the barcode toner images 72, 74, 76 based on the density detection becomes possible.

  As described above, in the present embodiment, for the JAN code or the Code 39 bar code that is advantageous for the occurrence of a reading error due to a decrease in image quality, the toner consumption is reduced by keeping the density of the toner patch 78 low. The density of the toner patch 78 is increased for QR codes and EAN-128 barcodes, which are disadvantageous to the occurrence of reading errors accompanying image quality degradation. Therefore, priority is given to ensuring good image quality by forming a barcode with a newer toner, and the toner consumption can also be changed by changing the density of the toner patch 78 in accordance with the barcode standard. Thus, it is possible to print a barcode with good quality while suppressing the running cost of the image forming apparatus 10.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. The fourth embodiment is also a modification of the second embodiment, and will be described with reference to the flowchart of FIG. 8 showing the printing operation.

  In steps 180 to 194 of the flowchart shown in FIG. 8, the same operations as those in steps 100 to 114 of the flowchart shown in FIG. 5 described in the second embodiment are performed.

  If the standard of the barcode to be printed is a JAN code (affirmative determination in step 188), as shown in FIG. 9A, the photosensitive belt 16 is associated with the toner image 74 of the JAN code. A small area toner patch 78D having a predetermined size is formed in the upper non-image area NA (step 196).

  In the case of a Code 39 barcode (affirmative determination in Step 190 after a negative determination in Step 188), as shown in FIG. 9B, the photosensitive belt is associated with the toner image 76 of the Code 39 barcode. A toner patch 78E having a medium area larger than the toner patch 78D is formed in the non-image area NA on the image 16 (step 198).

  In the case of a QR code (affirmative determination in step 192 after a negative determination in step 190) or in the case of an EAN-128 barcode (step 194 after a negative determination in step 192), the toner of the QR code The non-image area NA on the photoreceptor belt 16 is larger than the toner patch 78F in correspondence with the image or in correspondence with the EAN-128 barcode toner image 72 as shown in FIG. 9C. A large area toner patch 78F is formed (step 200/202).

  Also in this embodiment, as in the second embodiment, density determination (quality control) of barcode toner images 72, 74, and 76 based on density detection of toner patches 78D, 78E, and 78F having different sizes. ) Is possible.

  As described above, in the present embodiment, for JAN codes and Code 39 barcodes, the toner patch size (area) is reduced to reduce the amount of toner consumed while ensuring a desired image quality. For QR codes and EAN-128 barcodes, the size of the toner patch is increased, and barcodes are formed with newer toner to give priority to ensuring good image quality. By changing the size of the toner patch 78 in accordance with the barcode standard, it is possible to print a barcode with good quality while suppressing the toner consumption and the running cost of the image forming apparatus 10. it can.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described.

  Recently, there are an increasing number of cases in which color barcodes are printed on paper preprinted in color, and barcodes may be printed on recycled paper with low whiteness. In such a case, even if the toner patch 78 is formed to improve the barcode quality as described above, the barcode reading error may not be suppressed and the reading rate may not be improved. Therefore, the fifth embodiment improves the barcode reading rate when printing color barcodes or printing barcodes on recycled paper. The printing method of the image forming apparatus 10 is used for this method. The operation will be described with reference to the flowchart of FIG.

  In steps 220 to 226 of the flowchart shown in FIG. 10, the same operations as those in steps 100 to 106 of the flowchart shown in FIG. 5 described in the second embodiment are performed.

  Subsequently, the color CCD camera 66 provided above the paper feed cassette 20 in the image forming apparatus 10 (see FIG. 1) photographs the bar code printing position on the preprinted paper P (step 228), and the control unit 80 The color of the barcode printing position (background color) is identified from the photographed image, the barcode color is set to the complementary color of the background color (step 230), and printing is executed (step 232 / step 234).

  This complementary color is a color in the position facing each other on the hue circle, and is also called the opposite color (in the case of the 12 hue circle, 1-red ⇒ 2-reddish orange ⇒ 3-yellow-orange ⇒ 4-yellow ⇒ 5-yellow-green ⇒ 6-green ⇒ 7-blue-green ⇒ 8-green-blue ⇒ 9-blue ⇒ 10-blue-purple ⇒ 11-purple ⇒ 12-purple), for example, if the background color is “green” For example, the barcode color is “red” which is a complementary color of green, and if the background color is “yellow”, the barcode color is “blue purple” which is a complementary color of yellow. Further, in the recycled paper, when the whiteness decreases and the paper color is close to yellow-orange, the barcode color is “blue” which is a complementary color of “yellow-orange”.

  For reading and identifying the background color at the barcode printing position, for a printer or the like equipped with a scanner, the preprinted paper P is scanned in advance and the color pattern of the entire page is stored in the control unit 80, and the color pattern is read. You may make it perform using. In addition, although it does not support full color, it has a plurality of print engines 36 corresponding to specific colors such as red and blue, and if it is configured to select from these multiple colors, the barcode color is printed. Among possible hues, a color having the highest contrast with respect to the background color at the barcode forming position on the preprinted paper P is selected. For example, when the background color is “blue”, it is desirable that the barcode color be “yellow-orange” which is the complementary color. However, if yellow-orange is not printable, it is a color close to yellow-orange and blue. In contrast, “yellow” or “red” having high contrast is used. In addition, when the background color is “yellow”, it is desirable that the barcode color be “blue-purple” as its complementary color. “Blue” with high contrast is used.

  As a result, in this embodiment, the occurrence of barcode reading errors caused by a decrease in contrast between the barcode color and the background color (paper color) can be suppressed, and the reading rate can be improved.

  The present invention has been described in detail with reference to the first to fifth embodiments. However, the present invention is not limited to these embodiments, and various other modes can be implemented within the scope of the present invention. is there.

  For example, in the second to fourth embodiments described above, the case where the number, density, and size (area) of the toner patches 78 formed in the non-image area NA on the photosensitive belt 16 are individually changed will be described. However, the toner patch 78 may be formed by combining two or more of the above changing conditions according to the barcode standard.

1 is a configuration diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. 1 is a block diagram illustrating a schematic configuration of a control system of an image forming apparatus according to an embodiment of the present invention. (A)-(C) are top views which show an example of the EAN-128 barcode printed by the image forming apparatus which concerns on one Embodiment of this invention. FIG. 3 is a diagram illustrating a barcode toner image and a toner patch formed on the photosensitive belt according to the first exemplary embodiment of the present invention, as viewed from the direction of arrow B in FIG. 1. It is a flowchart which shows the flow of the printing operation | movement of the barcode which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows the flow of the printing operation | movement of the barcode which concerns on the 3rd Embodiment of this invention. FIGS. 7A to 7C are diagrams illustrating a barcode toner image and a toner patch formed on a photosensitive belt according to a third embodiment of the present invention. FIGS. It is a flowchart which shows the flow of the printing operation | movement of the barcode which concerns on the 4th Embodiment of this invention. FIGS. 7A to 7C are diagrams illustrating a barcode toner image and a toner patch formed on a photosensitive belt according to a fourth embodiment of the present invention. FIGS. It is a flowchart which shows the flow of the printing operation | movement of the barcode which concerns on the 5th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 16 Photosensitive belt 72, 74, 76 Toner image 78 Toner patch 80 Control unit (determination means)
IA Image area NA Non-image area P Preprinted paper (recording medium)

Claims (5)

In an image forming apparatus that forms a toner image on a surface of a photoreceptor and transfers the image to a recording medium to form an image including a barcode.
Wherein the non-image area where the toner image is not formed on the surface of the photoreceptor, a toner patch is formed corresponding to the toner image for the bar code,
Density detecting means for detecting the density of the toner patch;
Determination means for determining the quality of the barcode based on the density of the toner patch detected by the density detection means;
An image forming apparatus comprising:   The image forming apparatus according to claim 1, wherein the number of times the toner patch is formed is changed according to a standard of the barcode.   The image forming apparatus according to claim 1, wherein the density of the toner patch is changed according to a standard of the barcode.   The image forming apparatus according to claim 1, wherein a size of the toner patch is changed according to a standard of the barcode. A plurality of image forming means for forming images of different colors;
The barcode color is a complementary color of the background color of the barcode forming position in the recording medium, or a color having the highest contrast with respect to the background color among the hues that can be formed. The image forming apparatus according to any one of claims 1 to 4 .

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