JP2007025564A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control means of an optical medium sensor capable of correctly detecting a medium even with an already printed medium. <P>SOLUTION: In an image forming apparatus which detects optical characteristics of a material of a recording medium to discriminate the medium and performs print in an image formation condition corresponding to the medium discrimination result, optical detection is performed on a non-printing area of the medium to avoid optical detection on a printed area of an already printed paper, where judgement of optical characteristics of the material is difficult. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention detects an optical characteristic on the material of a recording medium, discriminates the media, and in an image forming apparatus that performs printing under an image forming condition according to the media discrimination result, malfunction caused by optical noise of printed paper is detected. The present invention relates to an optical media detection means that is avoided.

  2. Description of the Related Art Conventionally, an image forming apparatus that detects an optical characteristic on a material of a recording medium, performs media discrimination, and performs printing under an image forming condition according to the media discrimination result is optical as proposed in Patent Document 1. A media sensor is configured.

  FIG. 16 is a schematic configuration diagram of an optical media sensor image forming apparatus which is a conventional example of the present invention. FIG. 17 is a schematic structural diagram illustrating the configuration of the optical media sensor of FIG. FIG. 18 is a detection image for each medium of the optical media sensor in FIG.

  The configuration will be described below with reference to FIG. 01 is a color laser beam printer, which selectively conveys recording media of 02 and 03 by feed rollers of 04 and 05, passes through a 06 optical media sensor, and is conveyed to a 07 transfer belt.

  Reference numerals 08 to 11 denote photosensitive drum cartridges containing magenta, cyan, yellow, and black toner, respectively. The latent images are formed by the laser scanners 12, 13, 14, and 15, developed, and the toner images are transferred to a medium. Conduct an electrophotographic process. Reference numeral 16 denotes a heat fixing device configured to heat and fix a toner image and perform printing.

Reference numeral 30 is a media sensor, 33 is an LED, 34 is a CCD two-dimensional sensor, and 35 and 36 are lenses, and the reflected light is read out by irradiating the light of the LED 34 at a predetermined timing from feeding the media 32 in the 31 conveying path. Accordingly, the media determination is made by comparing the optical image shown in FIG. 17 with the optical characteristics previously analyzed for each media material.
JP 2002-182518 A

  However, according to the above-described conventional example, in particular, when printing preprinted paper such as official documents, etc., which has been printed in advance and whose paper size material is determined, when the preprinted area is applied to the optical detection position, the print pattern is changed. There is a problem in that it becomes optical noise, it is difficult to judge optical characteristics on the correct material, and the automatic media detection function is impaired.

The present invention has been devised to solve the above problems,
In the image forming apparatus that detects the optical characteristics on the material of the recording medium, performs media discrimination, and performs printing under image forming conditions according to the media discrimination result, the optical detection position is performed in a non-printing area on the media, The optical detection in the preprinted area of the preprinted paper where it is difficult to judge the optical characteristics of the material is avoided.

  The non-printing area is a non-printing guarantee area or an image mask area in the main scanning direction.

  The non-printing area is a non-printing guarantee area or an image mask area in the sub-scanning direction.

  Further, the optical media detection means main scanning direction position is arranged upstream of the laser irradiation equivalent position on the paper passing conveyance path in the electrophotographic process, and the optical detection is performed in the width of the non-print guarantee area or the image mask area at the leading edge in the paper conveying direction. The inside of the range is detected, and the paper feed start position and the media determination means are arranged close to each other.

  In addition, the optical media detection means is positioned in the sub-scanning direction position based on one of the one-side regulation or both-side regulation, and the optical detection position is in the non-printing guarantee area on the reference conveyance guide side in the sub-scanning direction. 4. The image forming apparatus according to claim 4, wherein an image mask area is detected within a width range.

  In addition, the preprinted paper data storage means for storing the correspondence information between the preprinted paper optical characteristic data at the optical detection position and the medium, and the optical characteristics of the detection area are analyzed by the optical media detection means, and the preprinted and nonprinted areas are analyzed. When the printed area data identifying means for identifying and the printed area data identifying means determine that the printed area data is non-printed area data, normal media discrimination is performed. An image forming apparatus having registered media identifying means for identifying registered media in comparison with the already-printed paper data storage means data, and performing printing under image forming conditions according to the registered media identifying means discrimination result.

  Further, when the registration medium identification means is not registered, the printing process is controlled to be stopped.

  If the registered media identification means is not registered, the printing process is suspended, a media information input request is displayed on the display panel or the host computer, and the printing process is resumed according to the inputted media information. A pre-printed paper data manual registration unit for registering characteristic data and input media information in the pre-printed paper data storage unit is provided.

  If the registered media identification means is not registered, the printing process is stopped and the paper is transported, the non-printing area outside the media detection detection area is scanned, and the detected non-printing area data media discrimination result is displayed. The preprinted paper data automatic registering means for automatically registering in the preprinted paper data storage means together with the optical characteristic data determined as above is provided.

  Further, a print image data analyzing means for generating optical feature data of optical detection position print data from image data at the time of printing, and an optical media detection means at the time of printing, from the detected media discrimination result, the table data storage means stores the print print image. An automatic printing paper data registration means for automatically registering correspondence information between optical characteristic data and media is provided.

  Further, a media detection control means is provided that can select the preprinted paper data storage means registration method and control method by input from a display panel or a host computer.

  The preprinted paper data storage means is a reference frequency storage means for adding reference frequency data for a predetermined period from registration. When the predetermined storage capacity is exceeded at the time of new registration, the reference frequency excluding protect data is low and the registration elapsed time is long. Data management control means for deleting data is taken.

  As described above, according to the present invention, in an image forming apparatus that detects optical characteristics on the material of a recording medium, performs media discrimination, and performs printing under image forming conditions according to the media discrimination result, The detection position is performed in the non-printing area on the medium, and the optical detection in the preprinted area of the preprinted paper where it is difficult to determine the optical characteristics of the material is avoided.

  The non-printing area is a non-printing guarantee area in the main scanning direction or a non-printing guarantee area or image mask area in the sub-scanning direction, and the position of the optical media detection means in the main scanning direction is a laser on a paper passing conveyance path in an electrophotographic process. Arranged upstream of the irradiation equivalent position, optical detection detects within the width of the non-print guarantee area or image mask area at the leading edge of the paper conveyance direction, and the paper feed start position and the media judging means are arranged close to each other to reduce the size of the apparatus There is an effect that can be achieved.

  Also, the preprinted paper data storage means for storing the correspondence information between the preprinted paper optical feature data at the optical detection position and the medium, and the optical feature of the detection area are analyzed by the optical media detection means to determine the preprinted area data. In this case, the optical characteristics of the detected media are compared with the already-printed paper data storage unit data, and the registered media identifying unit for identifying the registered media performs printing under the image forming conditions according to the registered media identifying unit discrimination result. Even if the already-printed area is applied to the media sensor optical detection position, it is possible to detect the media using the print pattern as identification information, the print pattern becomes optical noise, and it is difficult to judge the optical characteristics of the correct material. It also has the effect of solving the problem of the automatic media detection function.

  Further, in the registered media identification means configuration, if not registered, the preprinted paper data is manually or automatically registered, and the preprinted paper data storage means registration method and control method are optionally set from a display panel or a host computer. Media detection control means that can be selected by input, and the already-printed paper data storage means is a reference frequency storage means for adding reference frequency data for a predetermined period from the registration, and protects when a predetermined storage capacity is exceeded at the time of new registration By providing a data management control means for deleting data with a low reference frequency excluding data and a long registration elapsed time, there is an effect of providing an easy-to-use printed paper media detection function.

  Therefore, means for avoiding optical detection in the preprinted area and means for performing media detection using the print pattern as identification information are provided. In particular, preprinted paper in which the paper size material and the like are preprinted, such as a format of an official document, etc. When printing an image, if the already printed area is applied to the optical detection position, the print pattern becomes optical noise, making it difficult to determine the optical characteristics of the correct material, and to solve the problem of impairing the automatic media detection function. effective.

Example 1
FIG. 1 is a schematic configuration diagram for explaining the position of the media sensor apparatus according to the first embodiment of the present invention and the optical detection position on the medium. FIG. 2 is a schematic configuration diagram when the optical detection position on the medium in FIG. 1 is viewed from above the medium. This will be described below with reference to FIGS. Reference numerals 101 and 102 denote recording media which are conveyed in the direction of the photosensitive drum 105 as indicated by arrows 103 and 104. 106 is a media sensor which is disposed at a predetermined detection position 107 on the paper feed conveyance path, and irradiates light at a predetermined timing from the paper feed and reads the reflected light, thereby detecting the media on the conveyance path at the optical detection position 201 and The optical characteristic of 202 is read. Reference numeral 203 in FIG. 2 denotes a storage medium, and reference numerals 204, 108, and 109 denote printable areas. The printable area is an area where printing is performed by the image forming apparatus, and is set by masking the image around the media in order to prevent back smear due to image protrusion and fixing separation. The optical detection positions 201 and 202 are configured by sequence control means so as to detect the leading edge image mask area and the trailing edge image mask area in the sub-scanning direction, respectively.

(Example 2)
FIG. 3 is a schematic configuration diagram for explaining the position of the media sensor apparatus according to the second embodiment of the present invention and the optical detection position on the medium. FIG. 4 is a schematic configuration diagram when the optical detection position on the medium in FIG. 3 is viewed from above the medium. The second embodiment of the present invention is that a non-printing area in the main scanning direction is detected while a non-printing area in the sub-scanning direction is detected in the first embodiment.

  This will be described below with reference to FIGS. Reference numerals 301 and 302 denote recording media which are conveyed in the direction of the photosensitive drums 305 and 306 as indicated by arrows 303 and 304. Reference numerals 307 and 308 denote media sensors which are arranged at predetermined detection positions 309 and 310 on the paper feed conveyance path, and irradiate light at a predetermined timing from the paper feed and read the reflected light so that the media on the conveyance path is shown in FIG. The optical characteristics of the detection positions 401 and 402 are read. In FIG. 4, reference numeral 403 denotes a storage medium, and reference numerals 404, 311 and 312 denote printable areas. The optical detection positions 401 and 402 are configured by sequence control means so as to detect the right end image mask area or the left end image mask area in the main scanning direction, respectively. Thus, there is an effect peculiar to the present embodiment that the degree of freedom of the detection position of the sub-scanning method can be obtained by detecting the right end image mask region or the left end image mask region.

(Example 3)
FIG. 5 is a schematic configuration diagram for explaining the position of the media sensor apparatus according to the third embodiment of the present invention and the optical detection position on the medium. FIG. 6 is a schematic configuration diagram when the optical detection position on the medium in FIG. 5 is viewed from above the medium. In the third embodiment, in the first embodiment, the position of the media sensor is set at a position where the mask area in the sub-scanning direction including the rear end can be detected, whereas the position on the transport path is set to the laser irradiation equivalent position. The point is that the position is set to be the detection timing limited to the front image mask region. This will be described below with reference to FIGS. A recording medium 501 is conveyed in the direction of the photosensitive drum 504 by the conveying roller 503 in the direction of the arrow 502. The photosensitive drum 504 is charged by a charging roller 505 by rotation, a latent image is formed by a laser scanner 506, developed by a developing sleeve 507, and a toner image is transferred to a medium on a transfer belt 509 at a transfer position 508. carry out. Reference numeral 510 denotes a laser irradiation equivalent position, which is a position equivalent in sequence to the laser irradiation position 511.

  512 is a media sensor, which is disposed between the feed conveyance path laser irradiation equivalent position 510 and the leading edge image mask rear end equivalent position 513, and irradiates light at a predetermined timing from feeding and reads the reflected light to read the reflected medium. Is configured to read the optical characteristics of the optical detection position 601 shown in FIG. In FIG. 6, reference numeral 602 denotes a storage medium, and reference numeral 603 denotes a printable area. By detecting the leading edge image mask area in the sub-scanning direction with the media sensor arranged in front of the laser irradiation equivalent position 510 in this way, the paper feed conveyance path can be shortened, and the detection timing does not depend on the length of the paper in the sub-scanning direction. There is an effect that can be controlled.

Example 4
7 and 8 are schematic configuration diagrams for explaining the position of the media sensor device according to the fourth embodiment of the present invention and the optical detection position on the medium. The fourth embodiment solves the problem that the mask area moves depending on the media size in the main scanning direction in the second embodiment.

  FIG. 7 is a schematic configuration diagram for explaining an embodiment in the center reference method in which media conveyance is performed by matching the standards of the media center and the image center.

  Reference numerals 701 to 705 denote media of various sizes, and they are moved evenly like 708 and 709 by a paper feed guide 706 and a rack and pinion mechanism 707 connected to the paper feed guide, and both sides are regulated so as to be 710 media. 717 has a function of guiding to the center of the center, transporting it in the transport direction 712, and feeding it to the photosensitive drum 711.

  Reference numerals 713 and 714 denote media sensors which are connected to the paper feed guide 706 and always maintain a predetermined position from the paper feed guide, and a movement detection area mask area 718 from the minimum printable area 715 to the maximum printable area 716. The inside is installed at the detection position. By these controls, a media sensor arrangement method has been devised that reliably detects the right end or left end mask area.

  FIG. 8 is a schematic configuration diagram for explaining an embodiment of the one-side reference method in which media conveyance is performed with the media edge and the image edge as a reference to form an image.

  Reference numerals 801 to 805 denote media of various sizes, which have a function of transporting the medium while approaching the one-side reference 809 by a paper feed guide 806 and a skew feeding roller 807, transporting it in the 811 transport direction, and feeding it to the photosensitive drum 812.

  Reference numeral 808 denotes a media sensor which is connected to the paper feed guide 806 and always maintains a predetermined position from the paper feed guide 806 set to the one-side reference 809 and detects the position within the mask area 813 up to the maximum printable area 810. It is installed in. By these controls, a media sensor arrangement method has been devised that reliably detects the right end or left end mask area in the one-side reference method.

(Example 5)
FIG. 9 is a schematic configuration diagram illustrating a control block configuration of an optical media sensor having registered media identification means for identifying already printed paper according to a fifth embodiment of the present invention.

  FIG. 10 is a data configuration explanatory diagram for explaining the preprinted paper data storage means of the control block configuration of the optical media sensor shown in FIG.

  FIG. 11 is a flowchart for explaining control steps of the control block configuration media determination control unit of the optical media sensor shown in FIG.

  Reference numeral 901 denotes a media sensor that irradiates light at a predetermined timing and detects an image in which reflected light from the surface of a predetermined detection area of the medium is imaged on a two-dimensional sensor light receiving surface of a CMOS sensor or a CCD.

  A media determination processor 902 processes image information from the media sensor, performs media determination, and performs media determination related control in cooperation with engine control means 909 that controls the entire image forming apparatus. The engine control unit 909 is connected to the host computer 911 via the communication interface 912, develops print data into a bitmap image 910 by a print command sent from the host computer 911, and performs printing by an electrophotographic process. Reference numeral 913 denotes a display panel which is arranged on the image forming apparatus and displays the state on a display device 914 made up of an LCD or an LED, etc., and has an input means made up of an input switch 915 made up of a push switch, etc. It constitutes a function.

  The media determination processor 902 includes digital signal processing means (hereinafter referred to as DSP) 903 that processes the image signal from the media sensor 901 at high speed and in real time, and analyzes the input image data into several optical feature parameters. Reference numeral 904 denotes a media material determination unit, which includes a CPU core of the media determination control unit 906, a media material determination control step unit, and a media material optical characteristic table storage unit, and performs media material determination from the DSP 903 optical characteristic parameters. Reference numeral 907 denotes an already-printed area data determination means which is a characteristic feature of the fifth embodiment of the present invention, and includes a CPU core of the media determination control unit 906, an already-printed area determination control step means, and an already-printed paper data storage means 908. Is done.

  In the block configuration described above, the processing configuration of the already-printed area data determination means will be described with reference to FIG.

  When an image in a media detection area as indicated by 1005 to 1007 in FIG. 10 is input by the media sensor 901, three types of video data patterns 1008 to 1010 are input depending on the media (steps 1101 and 1102). .

  Based on the optical feature parameters extracted by the DSP 903 (step 1103), it is determined whether or not it is a print area by a product-sum operation process (neuronet process) in which weighting and threshold setting are performed in advance for each parameter (step 1103). Steps 1104 and 1105).

  In the case of the non-printing area 1007, the media material optical property table means is referred to from the optical feature parameter, and normal material media determination processing is performed (steps 1109 and 1110).

  In the case of the print area 1005 to 1006, the maximum feature value search is performed by the pattern correlation coefficient by referring to the detection pattern map 1003 of the data of the already-printed paper data storage unit 908 indicated by 1001 in FIG. If the correlation coefficient is equal to or greater than a predetermined value, the media information corresponding to the maximum correlation data is notified to the engine control means as a determination medium (steps 1106, 1107, 1111 and 1110).

  If it is determined in step 1107 that the optical feature data correlation coefficient is determined that there is no corresponding data, control is performed to execute the print stop process as shown in the flowchart of FIG. 12 (steps 1201, 1202, and 1203).

  According to the configuration and control configuration of the fifth embodiment of the present invention described above, the medium is determined even when the already printed paper is fed.

(Example 6)
FIG. 13 is a flowchart for explaining a manual registration control configuration of an optical media sensor having registered media identification means for identifying already-printed paper according to the sixth embodiment of the present invention.

  A feature of the sixth embodiment of the present invention is that control means is provided for manually registering data of already printed paper when it is determined in step 5107 of the fifth embodiment that there is no corresponding data in the optical feature data correlation coefficient determination. It is characterized by that.

  Hereinafter, the control configuration will be described with reference to the flowchart of FIG.

  If it is determined in step 1107 in FIG. 11 that there is no corresponding data in the optical feature data correlation coefficient determination, the engine control means is notified to execute the print processing temporarily and a media information input request is sent to the display panel and the host computer. The display is controlled to be displayed (steps 1301, 1302, and 1303).

  The user waits for media information input from the user for a predetermined time. If no information is input, printing is stopped (steps 1304, 1308, 1309, and 1310). If information is input, the printing process is resumed based on the input media information. The control means is configured to register the input media information together with the optical feature data in the already-printed paper data storage means (steps 1304, 1305, 1306, 1307).

  According to the configuration and the control configuration of the sixth embodiment of the present invention described above, printing is performed and media registration is performed even when there is no already-printed paper registration data.

(Example 7)
FIG. 14 is a flowchart for explaining an automatic registration control configuration of an optical media sensor having registered media identification means for identifying already printed paper according to the seventh embodiment of the present invention.

  A feature of the seventh embodiment of the present invention is that a control means is provided for automatically registering data of already printed paper when it is determined that there is no corresponding data in the optical feature data correlation coefficient determination in step 5107 of the fifth embodiment. It is characterized by that.

  Hereinafter, the control configuration will be described with reference to the flowchart of FIG.

  If it is determined in step 1107 in FIG. 11 that there is no corresponding data in the optical characteristic data correlation coefficient determination, the engine control means is notified to stop the printing process, and the paper conveyance process is performed, and the media sensor input is sub-scanned. Data is scanned by scanning in the direction (steps 1401, 1402, 1403, 1404).

  With respect to the input data, the already-printed data identification process described in the fifth embodiment is performed, and scanning is continued until the non-print data can be acquired. Perform (Steps 1405, 1406, 1411, 1412, 1413).

  When non-print data is acquired in the scan processing (steps 1405, 1406, 1411, 1412, and 1413), normal media material determination processing is performed on the data by the media material optical property table reference processing, and the optical characteristic data acquired initially. The control means is configured to automatically register the media information of the media material determination processing result in the already-printed paper storage means (steps 1407, 1408, 1409, 1410).

  According to the configuration and the control configuration of the seventh embodiment of the present invention described above, the preprinted paper medium is automatically registered even when there is no preprinted paper registration data.

(Example 8)
FIG. 15 is a schematic configuration diagram illustrating a control block configuration of an optical media sensor having registered media identification means for identifying already printed paper according to an eighth embodiment of the present invention.

  The feature of the eighth embodiment of the present invention is that, in the sixth and seventh embodiments, registration processing is performed by feeding already-printed paper, but a format or the like is printed by the image forming apparatus for the purpose of reprinting. In some cases, a pre-printed paper data automatic registration means for registering print paper data based on the print data is provided.

  That is, the image data of the media sensor detection area is extracted from the developed bitmap image of the print data, and is transmitted to the DSP of the media determination processor by the 1501 media detection area image transmission means to extract the optical feature data and the media sensor detection determination A preprinted paper data automatic registration control means for registering the medium as preprinted paper data is provided.

  In addition, the preprinted paper data registration control means of the sixth to eighth embodiments, including the fifth embodiment that does not perform the registration control described above, can be arbitrarily selected by input from a display panel or a host computer. It was taken.

  The preprinted paper data storage means is a reference frequency storage means for adding reference frequency data for a predetermined period from registration. When the predetermined storage capacity is exceeded at the time of new registration, the reference frequency excluding protect data is low and the registration elapsed time is long. Data management control means for deleting data is taken.

Schematic configuration diagram for explaining the position of the media sensor device according to the first embodiment of the present invention and the optical detection position on the medium Schematic configuration diagram of the optical detection position on the medium in FIG. 1 viewed from above the medium Schematic configuration diagram for explaining the position and the optical detection position on the medium in the apparatus of the media sensor according to the second embodiment of the present invention Schematic configuration diagram of the optical detection position on the medium in FIG. 3 viewed from above the medium The schematic block diagram explaining the position in the apparatus of the media sensor which is 3rd Example of this invention, and the optical detection position on a medium FIG. 5 is a schematic configuration diagram when the optical detection position on the medium in FIG. 5 is viewed from above the medium. Schematic configuration diagram for explaining the position of the media sensor in the fourth embodiment of the present invention and the optical detection position on the media. Schematic configuration diagram for explaining the position of the media sensor in the fourth embodiment of the present invention and the optical detection position on the media. Schematic configuration diagram illustrating a control block configuration of an optical media sensor having registered media identification means for identifying already printed paper according to a fifth embodiment of the present invention. 9 is a data configuration explanatory diagram for explaining the preprinted paper data storage means of the control block configuration of the optical media sensor. FIG. 9 is a flowchart for explaining the control steps of the control block configuration media determination control unit of the optical media sensor. FIG. 9 is a flowchart for explaining the control steps of the control block configuration media determination control unit of the optical media sensor. FIG. 9 is a flowchart for explaining a manual registration control configuration of an optical media sensor having registered media identification means for identifying already-printed paper according to a sixth embodiment of the present invention. FIG. 9 is a flowchart for explaining an automatic registration control configuration of an optical media sensor having registered media identification means for identifying already-printed paper according to a seventh embodiment of the present invention. Schematic configuration diagram illustrating a control block configuration of an optical media sensor having registered media identification means for identifying already printed paper according to an eighth embodiment of the present invention. 1 is a schematic configuration diagram of an optical media sensor image forming apparatus that is a conventional example of the present invention. Conventional Example of the Present Invention FIG. 16 Schematic structure diagram illustrating the configuration of an optical media sensor Conventional Example of Present Invention FIG. 17 Explanatory diagram of detected image for each medium of optical media sensor

Explanation of symbols

101, 102 Recording medium 103, 104 Conveying direction 105 Photosensitive drum 106 Media sensor 107 Detection position 108, 109 Printable area 201, 202 Optical detection position 203 Storage medium 204 Printable area 205 Conveying direction 301, 302 Recording medium 303, 304 Conveyance Direction 305, 306 Photosensitive drum 307, 308 Media sensor 309, 310 Detection position 311, 312 Printable area 401, 402 Optical detection position 403 Storage medium 404 Printable area 405 Conveyance direction 501 Recording medium 502 Conveyance direction 503 Conveyance roller 504 Photosensitive drum 505 Charging roller 506 Laser scanner 507 Development sleeve 508 Transfer position 509 Transfer belt 510 Laser irradiation equivalent position 511 Laser irradiation position 512 Rear sensor 513 Front image mask rear end equivalent position 601 Optical detection position 602 Storage medium 603 Printable area 701 to 705 Various sizes of media 706 Paper feed guide 707 Rack and pinion mechanisms 708 and 709 Both-side restricted movement range 710 Media 711 Photosensitive drum 712 Conveyance Direction 713, 714 Media sensor 715 Minimum printable area 716 Maximum printable area 717 Center center 718 Movement detection area mask area 801-805 Various sizes of media 806 Paper feed guide 807 Inclined feed roller 808 Media sensor 809 One side reference 810 Maximum print Possible area 811 Transport direction 812 Photosensitive drum 813 Mask area 901 Media sensor 902 Media judgment processor 903 Digital signal processing means (DSP)
904 Media material determination means 906 Media determination control section 907 Preprinted area data determination means 908 Preprinted paper data storage means 909 Engine control means 910 Bitmap image 911 Host computer 912 Communication interface 913 Display panel 914 Display device 915 Input switch 1001 Preprinted Paper data storage means 1002 Optical feature data 1003 to 1005 Detection pattern map 1005 to 1007 Media detection area 1008 to 1010 Video data pattern 1101 to 1110 Processing steps 1201 to 1203 in FIG. 11 Processing steps 1301 to 1110 in FIG. Processing steps 1401 to 1413 in the flowchart Processing step 1501 in the flowchart in FIG. 14 Media detection Rear image transmission means 01 Color laser beam printer 02, 03 Recording medium 04, 05 Paper feed roller 06 Optical media sensor 07 Transfer belt 08-11 Photosensitive drum cartridge 12, 13, 14, 15 Laser scanner 16 Heat fixing device 30 Media sensor 33 led
34 CCD two-dimensional sensor 35, 36 Lens 31 Transport path 32 Media 43, 44, 45 Detection image according to material

Claims (12)

  In the image forming apparatus that detects the optical characteristics on the material of the recording medium, performs media discrimination, and performs printing under image forming conditions according to the media discrimination result, the optical detection position is performed in a non-printing area on the media, An image forming apparatus having optical media detecting means, wherein optical detection in an already printed area is avoided.   The image forming apparatus according to claim 1, wherein the non-printing area is a non-printing guarantee area or an image mask area in a main scanning direction.   The image forming apparatus according to claim 1, wherein the non-printing area is a non-printing guarantee area or an image mask area in a sub-scanning direction.   The position in the main scanning direction of the optical media detection means is arranged upstream of the laser irradiation equivalent position on the paper passing conveyance path in the electrophotographic process, and the optical detection is within the width of the non-print guarantee area or the image mask area at the front end in the paper conveying direction. The image forming apparatus according to claim 2, wherein the sheet feeding start position and the medium determination unit are arranged close to each other.   The position of the optical media detection means in the sub-scanning direction is arranged based on one of the one-side regulation or the both-side regulation of the sheet conveyance guide means, and the optical detection position is the non-printing guarantee area or image mask on the reference conveyance guide side in the sub-scanning direction. The image forming apparatus according to claim 3, wherein the image forming apparatus detects an area within the width of the area.   Pre-printed paper data storage means for storing the pre-printed paper optical feature data at the optical detection position and the corresponding information as registered media for pre-printed paper and optical media detection means for analyzing the optical characteristics of the detection area and pre-printing The printed area data identification means for distinguishing between the printed area and the non-printed area, and when the printed area data identifying means determines that the printed area data is non-printed area data, the normal media discrimination is performed. An image forming apparatus that includes a registered medium identifying unit that compares the optical characteristics of a medium with the already-printed paper data storage unit data and identifies a registered medium, and performs printing under an image forming condition according to a registered media identifying unit determination result.   The image forming apparatus according to claim 6, wherein the printing process is controlled to stop when the medium identification unit is not registered.   If the media identification means is not registered, the printing process is suspended, a media information input request is displayed on the display panel or the host computer, and the printing process is resumed according to the input media information and the detected optical characteristic data 7. The image forming apparatus according to claim 6, further comprising pre-printed paper data manual registration means for registering input media information in the pre-printed paper data storage means.   If the media identification means is not registered, the printing process is stopped and the paper is transported, the non-printing area outside the media detection detection area is scanned, and the detected non-printing area data media determination result is determined as the already printed area. 7. The image forming apparatus according to claim 6, further comprising pre-printed paper data automatic registration means for automatically registering with the pre-printed paper data storage means together with optical feature data.   The print image data analyzing means for generating optical feature data of the optical detection position print data from the image data at the time of printing and the optical feature of the print print image in the table data storage means from the result of the media discrimination of the detected optical media detection means at the time of printing. 7. The image forming apparatus according to claim 6, further comprising pre-printed paper data automatic registration means for automatically registering correspondence information between data and media.   11. The image forming apparatus according to claim 6, further comprising a media detection control unit capable of arbitrarily selecting the preprinted paper data storage unit registration method and the control method by input from a display panel or a host computer.   The pre-printed paper data storage means includes reference frequency storage means for adding reference frequency data for a predetermined period from registration, and data having a low registration frequency and a long registration elapsed time when the storage capacity exceeds a predetermined storage capacity at the time of new registration. 7. The image forming apparatus according to claim 6, further comprising a data management control unit to be deleted.

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