JP6620612B2 - Image processing device - Google Patents

Description

  The present invention relates to an image processing apparatus.

  In an image forming apparatus, an image reading function for reading an image after formation may be provided, and feedback may be provided for color conversion processing control during image formation.

  In Patent Document 1, when a color is specified with a color sample and printed, it is desired to faithfully reproduce the color of the color sample, so that the inspection of the area is strictly performed, but the color mixture ratio of RGB or YMCK is specified. In response to issues that cannot be inspected by distinguishing between the designated area and the area specified by the color sample, the criteria for special color (special color) designation areas are made stricter than those for areas other than spot color designation. It is described that it is performed on a scale close to the visual characteristics of.

JP 2013-005092 A

  When an image reading unit arranged on the downstream side of the image forming unit inspects an image after forming the image, if there is a special color (for example, gold, silver, clear, etc.), the accuracy of the image inspection is deteriorated. There is a case.

  An object of the present invention is to obtain an image processing apparatus capable of performing an image forming process by excluding a special color from an image inspection target.

  According to the first aspect of the present invention, there is provided a sorting unit that sorts colors when color conversion is performed for image formation according to whether or not the color corresponds to a preset color, and a plurality of colors sorted by the sorting unit. An image forming unit that forms an image on a recording medium in an overlapping manner, and a color other than the specific color formed on the recording medium before forming an image using the specific color sorted by the sorting unit. And an image inspection unit that inspects a color image.

  According to a second aspect of the present invention, in the first aspect of the present invention, the recording medium of the image forming unit is a conveyance path of the recording medium from the downstream side of the recording medium in the conveyance direction of the recording medium. The peripheral circuit for returning to the upstream side in the transport direction is provided, and an image to be subjected to image inspection is formed first, and an image other than the image inspection target is formed later.

  According to a third aspect of the present invention, in the invention of the second aspect, the peripheral circuit is an existing conveyance path that reverses the front and back surfaces of the recording medium and sends the reverse to the image forming unit. By repeating, an image is formed for each color sorted by the sorting means on the same surface of the recording medium.

  According to a fourth aspect of the present invention, in the first aspect of the present invention, the image forming unit is disposed upstream of the image inspection unit in the conveyance direction of the recording medium and forms an image to be inspected. And a second image forming unit arranged on the downstream side of the recording medium in the transport direction of the recording medium to form an image other than the image inspection target.

  According to the first aspect of the present invention, the special color can be excluded from the image inspection target and the image forming process can be performed.

  According to the second aspect of the present invention, it is possible to form an image on a recording medium so as to be overlapped in a plurality of times by a single image forming means.

  According to invention of Claim 3, the existing conveyance path can be utilized.

  According to the invention described in claim 4, it is possible to share the image formation of the image inspection object and the image outside the image inspection object using different image forming means.

1 is a schematic configuration diagram illustrating an example of a configuration of an image forming apparatus according to a first embodiment. 1 is a schematic configuration diagram illustrating an example of a configuration of a built-in image sensor provided in an image forming apparatus according to a first embodiment. It is a block diagram of a control system concerning a 1st embodiment. FIG. 2 is a schematic diagram showing the functions of the image forming apparatus according to the first embodiment in blocks. It is a front view (inspection color setting screen) of a UI device. 4 is a flowchart illustrating a control routine for executing a printing process and an inspection process based on whether or not an inspection target is necessary according to the first embodiment. FIG. 5 is a schematic diagram showing functions of an image forming apparatus according to a second embodiment in blocks.

“First Embodiment”
(Overall configuration of image forming apparatus)
As shown in FIG. 1, the image forming apparatus 10 according to the first embodiment selectively forms a full-color image and a black-and-white image, and includes a first housing 10 </ b> A that is an image forming unit, A second housing 10B connected to the housing 10A. An image processing unit 13 that performs image processing on image data supplied from an external device such as a computer is provided on the upper portion of the second housing 10B.

  In this specification, “image formation” and “printing” are treated as synonymous. That is, for example, an apparatus for developing an electrostatic latent image using a charged toner is commonly referred to as an “image forming apparatus”, and forms of image formation on paper include “single-sided printing”, “double-sided printing”, “Printed matter” or the like is applied as a common name. The first embodiment is not limited to image formation using an electrostatic latent image, but also includes image formation (printing) using general ink. Therefore, “image formation” and “printing” are performed as necessary. "".

  On the upper part of the first housing 10A, yellow (Y), magenta (M), cyan (C), and black (K) as normal colors and gold as a first special color that is a specific color Toner cartridges 14Y, 14M, 14C, 14K, 14G, and 14S are provided that store toners of silver (S) as the second special color (G) and a specific color.

  In the first embodiment, gold and silver are exemplified as the first special color and the second special color. However, the regular reflectance is higher than that of at least yellow, magenta, cyan, and black, and the diffuse reflectance is low. A color with a metallic luster can be selected, and in addition to gold and silver applied in the first embodiment, white (W), clear (CL), and the like are applicable.

  Hereinafter, each color of YMCK is referred to as a normal color, the other colors are referred to as special colors, and a special color belonging to the color having the metallic glossiness among the special colors is referred to as a metallic glossy special color.

  In the following description, the first special color (G), the second special color (S), yellow (Y), magenta (M), cyan (C), and black (K) are distinguished for each component. Will be described by adding a letter of G, S, Y, M, C, or K after a number as a symbol. When the first special color (G), the second special color (S), yellow (Y), magenta (M), cyan (C), and black (K) are not distinguished, G, S, Y, M , C and K are omitted.

  Under the toner cartridges 14, six image forming units 16 G, 16 S, 16 Y, 16 M, 16 C, and 16 K (collectively referred to as “image forming units 16”) corresponding to the toners of the respective colors are placed in the toner cartridges 14. It is provided to correspond.

  The exposure devices 40G, 40S, 40Y, 40M, 40C, and 40K (collectively referred to as “exposure device 40”) provided for each image forming unit 16 are prints that have been subjected to image processing by the image processing unit 13 described above. Image data is received from the image processing unit 13. Then, a light beam modulated in accordance with the image data is irradiated to image holders 18G, 18S, 18Y, 18M, 18C, and 18K (hereinafter collectively referred to as “image holder 18”). .

  In each image forming unit 16, an electrostatic latent image is formed on each image carrier 18 by irradiating each image carrier 18 with the light beam L from each exposure device 40.

  Around each image carrier 18, a corona discharge (non-contact charging) scorotron charger that charges the image carrier 18 and an electrostatic latent image formed on the image carrier 18 by the exposure device 40 are developed. A developing device that develops with toner, which is an example of an agent, a blade that removes the developer remaining on the image carrier 18 after transfer, and a static eliminator that performs static elimination by irradiating the image carrier 18 after transfer with light. Is provided. The scorotron charger, the developing device, the blade, and the static eliminator are arranged in this order from the upstream side to the downstream side in the rotation direction of the image carrier 18 so as to face the surface of the image carrier 18.

  A transfer unit 32 is provided below each image forming unit 16. The transfer unit 32 includes an annular intermediate transfer belt 34 that is in contact with each image carrier 18, and primary transfer rolls 36 </ b> G, 36 </ b> S, 36 </ b> Y that multiplex-transfer the toner image formed on each image carrier 18 onto the intermediate transfer belt 34. 36M, 36C, 36K (collectively referred to as “primary transfer roll 36”).

  The intermediate transfer belt 34 includes a drive roll 38 that is driven by a motor (not shown), a tension applying roll 41 that applies tension to the intermediate transfer belt 34, an opposing roll 42 that faces a secondary transfer roll 62 described below, It is wound around a plurality of winding rolls 44. And it is circularly moved in one direction (counterclockwise direction in FIG. 1) by the drive roll 38.

  Each primary transfer roll 36 is disposed opposite to the image carrier 18 of each image forming unit 16 with the intermediate transfer belt 34 interposed therebetween. The primary transfer roll 36 is applied with a transfer bias voltage having a polarity opposite to the toner polarity by a power supply unit (not shown). With this configuration, the toner image formed on the image carrier 18 is transferred to the intermediate transfer belt 34.

  On the opposite side of the drive roll 38 across the intermediate transfer belt 34, there is provided a removing device 46 that removes residual toner, paper dust and the like on the intermediate transfer belt 34 by bringing the blade into contact with the intermediate transfer belt 34. .

  Below the transfer unit 32, a plurality of paper storage units 48 that store recording media P as an example of a medium such as paper are provided. Each of the sheet storage portions 48 can be pulled out from the first housing 10A. A delivery roll 52 that feeds the paper P from each paper storage section 48 to the transport path 60 is provided above one end side of each paper storage section 48 (right side in front view in FIG. 1).

  In each paper storage portion 48, a bottom plate 50 on which the paper P is placed is provided. The bottom plate 50 is lowered by an instruction from a control means (not shown) when the paper storage portion 48 is pulled out from the first housing 10A. When the bottom plate 50 is lowered, a space for the user to replenish the paper P is formed in the paper storage portion 48.

  When the paper storage portion 48 pulled out from the first housing 10A is attached to the first housing 10A, the bottom plate 50 is raised by an instruction from the control means. By raising the bottom plate 50, the uppermost sheet P placed on the bottom plate 50 and the delivery roll 52 come into contact with each other.

  A separation roll 56 is provided on the downstream side in the paper conveyance direction of the delivery roll 52 (hereinafter sometimes simply referred to as “downstream side”), and separates the paper P that has been delivered from the paper storage portion 48 one by one. ing. A plurality of transport rolls 54 that transport the paper P downstream in the transport direction are provided on the downstream side of the separation roll 56.

  The conveyance path 60 provided between the paper storage unit 48 and the transfer unit 32 reverses the paper P sent out from the paper storage unit 48 to the left side when viewed from the front in FIG. Further, the second direction changing portion 60B extends to the transfer position T between the secondary transfer roll 62 and the opposing roll 42 so as to be reversed to the right in the front view in FIG.

  The secondary transfer roll 62 is applied with a transfer bias voltage having a polarity opposite to the toner polarity by a power feeding unit (not shown). With this configuration, each color toner image transferred onto the intermediate transfer belt 34 is secondarily transferred onto the paper P conveyed along the conveyance path 60 by the secondary transfer roll 62.

  A preliminary path 66 extending from the side surface of the first housing 10 </ b> A is provided so as to join the second direction changing portion 60 </ b> B of the transport path 60. The paper P sent out from another paper storage unit (not shown) arranged adjacent to the first housing 10 </ b> A can enter the transport path 60 through the spare path 66.

  On the downstream side of the transfer position T, a plurality of conveyance belts 70 that convey the paper P on which the toner image has been transferred toward the second casing 10B are provided in the first casing 10A, and are conveyed to the conveyance belt 70. A transport belt 80 that transports the paper P downstream is provided in the second housing 10B.

  Each of the plurality of conveyor belts 70 and the conveyor belt 80 is formed in an annular shape, and is wound around a pair of winding rolls 72. The pair of winding rolls 72 are respectively arranged on the upstream side and the downstream side in the transport direction of the paper P, and when one of them is rotationally driven, the transport belt 70 (transport belt 80) is moved in one direction (the timepiece in FIG. 1). Cycle in the direction of rotation).

  A fixing unit 82 for fixing the toner image transferred onto the surface of the paper P to the paper P with heat and pressure is provided on the downstream side of the conveyance belt 80.

  The fixing unit 82 includes a fixing belt 84 and a pressure roll 88 disposed so as to contact the fixing belt 84 from below. A fixing unit N is formed between the fixing belt 84 and the pressure roll 88 to fix the toner image by pressurizing and heating the paper P.

The fixing belt 84 is formed in an annular shape and is wound around the drive roll 89 and the driven roll 90. The drive roll 89 faces the pressure roll 88 from above,
The driven roll 90 is disposed above the drive roll 89.

  Each of the driving roll 89 and the driven roll 90 includes a heating unit such as a halogen heater. As a result, the fixing belt 84 is heated.

  As shown in FIG. 1, a conveyance belt 108 is provided on the downstream side of the fixing unit 82 to convey the paper P sent out from the fixing unit 82 to the downstream side.

  A cooling unit 110 that cools the paper P heated by the fixing unit 82 is provided on the downstream side of the conveyance belt 108.

  The cooling unit 110 includes an absorption device 112 that absorbs the heat of the paper P, and a pressing device 114 that presses the paper P against the absorption device 112. The absorption device 112 is disposed on one side (upper side in FIG. 1) with respect to the conveyance path 60, and the pressing device 114 is disposed on the other side (lower side in FIG. 1).

  The absorption device 112 includes an annular absorption belt 116 that contacts the paper P and absorbs the heat of the paper P. The absorption belt 116 is wound around a driving roll 120 that transmits a driving force to the absorption belt 116 and a plurality of winding rolls 118.

  A heat sink 122 made of, for example, an aluminum material is provided on the inner peripheral side of the absorption belt 116 to dissipate the heat absorbed by the absorption belt 116 in contact with the absorption belt 116 in a planar shape.

  Further, a fan 128 for removing heat from the heat sink 122 and discharging hot air to the outside is disposed on the back side of the second housing 10B (the back side of the paper surface shown in FIG. 1).

  The pressing device 114 that presses the paper P against the absorbing device 112 includes an annular pressing belt 130 that conveys the paper P while pressing the paper P against the absorbing belt 116. The pressing belt 130 is wound around a plurality of winding rolls 132.

  On the downstream side of the cooling unit 110, there is provided a correction device 140 that conveys the paper P with the paper P interposed therebetween and corrects the curl of the paper P.

  An image reading device (built-in image sensor 200) that detects a toner density defect, an image defect, an image position defect, and the like of the toner image fixed on the paper P is provided on the downstream side of the correction device 140. Details of the built-in image sensor 200 will be described later.

  On the downstream side of the built-in image sensor 200, a discharge roll 198 that discharges the sheet P on which an image is formed on one side to a discharge unit 196 attached to the side surface of the second housing 10B is provided.

  On the other hand, when images are formed on both sides, the paper P sent from the built-in image sensor 200 is conveyed to a front / back reversing path 194 provided on the downstream side of the built-in image sensor 200.

  The front / back reversing path 194 includes a branch path 194A branched from the transport path 60, a paper transport path for transporting the paper P transported along the branch path 194A toward the first housing 10A, and a paper transport path 194B. A front / back reversing path 194 </ b> C is provided that reverses the paper P conveyed along the reverse direction and reverses the paper P so as to reverse the front and back.

  With this configuration, the paper P that has been switched back by the front / back reversing path 194C is transported toward the first housing 10A, and further enters the transport path 60 provided above the paper storage portion 48, so that the transfer position T Will be sent again.

(Built-in image sensor 200)
The image forming apparatus 10 according to the first embodiment includes the built-in image sensor 200 on the downstream side of the correction device 140 as described above. The built-in image sensor 200 is used for detecting whether or not an image formed on the paper P by the image forming unit 16 is abnormal.

  The built-in image sensor 200 in this case has a function as a means for measuring gradation reproducibility and color reproducibility of the image forming unit 16. In addition, in order to maintain the function as the measurement unit normally, the built-in image sensor 200 may be calibrated regularly or irregularly.

  In the following description, the length direction of the image forming apparatus 10 (sub-scanning direction that is the conveyance direction of the paper P) is the X direction, the height direction of the apparatus is the Y direction, and the depth direction of the apparatus (main scanning direction) is the Z direction. (See FIGS. 1 and 2).

  As shown in FIG. 2, the built-in image sensor 200, which is an example of an image reading apparatus, includes an illumination unit 202 that emits light toward the paper P on which an image is recorded, and a paper P that is emitted from the illumination unit 202. An image forming unit 208 having an image forming optical system 206 that forms an image of the reflected light on the CCD sensor 204, and a setting unit 210 provided with various standards and the like when the built-in image sensor 200 is used or calibrated. I have.

  The CCD sensor 204 according to the first embodiment includes a plurality of light receiving elements (for example, photodiodes) arranged along a direction corresponding to the main scanning direction, A green image sensor and a blue image sensor are provided. Each color image sensor is provided with a filter that transmits light of each color component on the light receiving surface of the light receiving element.

Due to the structure of the CCD sensor 204, the built-in image sensor 200 may be referred to as an inline sensor (ILS) or the like. ).
Each color image sensor outputs, as a signal, the electric charge accumulated according to the amount of each color component of the light received by the light receiving element.

  The illumination unit 202 is disposed on the upper side of the conveyance path 60 of the paper P, and a pair of first lamp 212A and second lamp 212B (hereinafter collectively referred to as “long” in the Z direction (main scanning direction). It may be referred to as “lamp 212”).

  As the lamp 212, for example, a fluorescent lamp, a xenon lamp, or a plurality of white LEDs (not shown) arranged along the main scanning direction is used.

  The length of the irradiation range of the lamp 212 is set larger than the width of the maximum sheet P to be conveyed. The lamp 212 is arranged symmetrically with respect to the optical axis OA (designed optical axis) that is reflected by the paper P and travels toward the image forming unit 208.

  The light irradiated from the lamp 212 is configured to irradiate the irradiation position D of the transparent window glass 286 on the transport path 60 between the first lamp 212A and the second lamp 212B.

  In the window glass 286, the irradiation area irradiated with light from the lamp 212 is an area that overlaps the area through which the image forming area of the paper P passes on the setting unit 210, and is formed on the paper P on the transport path 60. An area where an image is read by the CCD sensor 204 is configured to include a predetermined area (image reading area).

  In addition, the imaging optical system 206 includes a first mirror 214 that reflects the light guided along the optical axis OA in the X direction (downstream in the transport direction of the paper P in the first embodiment), and a first mirror. The second mirror 216 that reflects the light reflected by 214 upward, the third mirror 218 that reflects the light reflected by the second mirror 216 upstream in the transport direction of the paper P, and the light reflected by the third mirror 218 A lens 220 that focuses (images) on the CCD sensor 204 and a light amount diaphragm unit 224 (224L, 224S, 224U)) are mainly configured.

  The length of the first mirror 214 in the Z direction is larger than the maximum width of the paper P. Then, the first mirror 214, the second mirror 216, and the third mirror 218 are respectively condensing (condensing) the reflected light of the paper P incident on the imaging optical system 206 in the Z direction (main scanning direction). It is designed to reflect. Thus, the reflected light from each part in the width direction of the paper P is made incident on the substantially cylindrical lens 220.

  The built-in image sensor 200 is configured such that the CCD sensor 204 outputs (feeds back) the imaged light, that is, a signal corresponding to the image density, to the control device 20 (see FIG. 1) of the image forming apparatus 10. .

  The control device 20 performs processing for correcting an image formed in the image forming unit 16 based on a signal input from the built-in image sensor 200. As an example of processing for correcting an image, correction of a tone adjustment LUT (lookup table) of the image forming apparatus 10 can be given.

  Other examples of correction include correction of the intensity of irradiation light by the exposure apparatus 40 based on a signal input from the built-in image sensor 200, the image formation position, and the like, and correction of the development potential and transfer current value.

  The setting unit 210 includes a reference roll 226 that is long in the Z direction. The reference roll 226 is formed in a polygonal cylindrical shape in which a predetermined number of surfaces are formed in the circumferential direction. In the reference roll 226 according to the first embodiment, a polygonal cylindrical shape having 10 surfaces is used. Has been.

  As shown in FIG. 2, the reference roll 226 detects the image of the paper P by the built-in image sensor 200 and the detection reference surface 228 (basic color is black) directed toward the conveyance path 60 when the image of the paper P is detected. And a retreating surface 230 directed toward the conveyance path when not performing, and each of the other surfaces functions as a reference surface (color reference surface) for each color used in color gamut correction processing or the like.

  The reference roll 226 is configured to switch the surface to be directed to the conveyance path 60 side by rotating around the rotation shaft 226A. The surface of the reference roll 226 is switched by the control circuit 100 provided on the circuit board 262.

  The retracting surface 230 has a circumferential width larger than that of other surfaces. The retreat surface 230 is a guide surface that guides the paper P when the built-in image sensor 200 does not detect the image of the paper P.

  As shown in FIG. 3, the control device 20 that controls the image forming apparatus 10 according to the first embodiment is formed in the image forming unit 16 based on the signal from the built-in image sensor 200 as described above. It has a function to correct images. The control device 20 also has a function of controlling calibration of the built-in image sensor 200 (for example, calibration of the CCD sensor 204 described above).

  The control device 20 includes a CPU (Central Processing Unit) 20A, a ROM (Read Only Memory) 20B, a RAM (Random Access Memory) 20C, and an input / output port 20D. Each is connected to each other via a bus 20E such as an address bus, a data bus, and a control bus.

  Various programs are stored in the ROM 20B, and various controls are performed by the CPU 20A reading the programs from the ROM 20B, developing them in the RAM 20C, and executing them.

  Note that a non-volatile storage medium (NVM) that stores various types of information that must be retained even when the power switch of the apparatus is turned off may be provided.

  A user interface device (UI device) 30, an image formation control unit 102, and a control circuit 100 of the built-in image sensor 200 are connected to the input / output port 20D.

  The UI device 30 includes, for example, a touch panel display in which a transmissive touch panel is superimposed on a display. Various types of information are displayed on the display surface of the display, and information and instructions are received when the user touches the touch panel. In the first embodiment, an example in which the UI device 30 is applied has been described. However, the present invention is not limited to this, and an operation unit provided with a display unit such as a liquid crystal display and a numeric keypad or operation buttons. And may be provided separately.

  FIG. 4 is a schematic diagram showing the functions of the image forming apparatus 10 having the above configuration in a block form.

  The image processing unit 300 is an example of a sorting unit, and receives document image data Dg from the image forming unit 302 and converts it into print image data Di.

  FIG. 4 shows the contrast between the printing unit 304, the paper feeding unit 306, the paper transport unit 308, and the paper discharge unit 310 described in blocks in FIG.

  The printing unit 304 is an example of an image forming unit and corresponds to the image forming unit 16 in FIG.

  The paper feed unit 306 corresponds to the paper storage unit 48, the delivery roll 52, and the separation roll 56 of FIG.

  The paper transport unit 308 corresponds to a roll and belt-type transport member along the transport path 60 in FIG.

  The paper discharge unit 310 corresponds to the discharge unit 196 and the discharge roll 198 in FIG.

  Further, the intermediate printed material Pc is the paper P returned to the upstream side of the printing unit 304, and the final printed material Ps is the paper P for which all processing has been completed.

  Here, in the first embodiment, yellow (Y), magenta (M), cyan (C), and black (K) toners are used, and the first special color and the second special color are used. Based on the inspection by the built-in image sensor 200 on the image of the paper P formed without including the representative metallic glossy special color, that is, based on the defect detection including the toner density defect, the image defect, and the image position defect. Feedback correction is performed.

  On the other hand, with respect to the image on the paper P on which an image is formed using each toner of a metallic glossy special color including gold (G) applied as the first special color and silver (S) applied as the second special color. Inspection by the image sensor 200 is not performed.

  That is, the feedback correction in the image processing unit 300 based on the defect detection including the toner density defect, the image defect, and the image position defect in the defect determination unit 312 illustrated in FIG. 4 is not performed.

  For example, gold and silver pigments have higher regular reflectance, lower diffuse reflectance, and metallic luster than at least yellow, magenta, cyan, and black. For this reason, the special color has poorer defect detection accuracy by the built-in image sensor 200 than the yellow, magenta, cyan, and black toners.

  That is, due to the reflected light of the lamp 212, so-called fogging and backlighting phenomenon occur, and it becomes difficult to read an image with the CCD sensor 204.

(Sorting of print image data)
Therefore, in the first embodiment, when the print image data includes a metallic glossy special color including gold (G) applied as the first special color and silver (S) applied as the second special color. The image processing unit 300, which is an example of sorting means, sorts the first print image data DiA in yellow, magenta, cyan, and black, and the second print image data DiB in gold and silver.

  Whether it belongs to the first print image data DiA or the second print image data DiB is determined as an initial setting as shown in Table 1 below.

なお、表１では、初期設定として各トナー色を固定的に検査対象の要否を定めたが、図５に示されるように、特別色を対象として、ＵＩ装置３０のタッチ操作によって、設定変更可能としてもよい。例えば、内蔵イメージセンサ２００のランプ２１２の光量を通常よりも暗くして、ＹＭＣＫの検査精度よりは劣るが、ゴールド及びシルバー等を検査対象としてもよい。

In Table 1, the necessity of inspecting each toner color is fixed as an initial setting. However, as shown in FIG. 5, the setting is changed by touch operation of the UI device 30 for a special color. It may be possible. For example, the amount of light of the lamp 212 of the built-in image sensor 200 is made darker than usual, which is inferior to the YMCK inspection accuracy, but gold, silver, or the like may be the inspection target.

  Further, since there are types of white having different reflectances, the necessity of inspection may be set depending on the type of white toner to be applied.

  As shown in FIG. 4, when the first print image data DiA and the second print image data DiB are sent to the printing unit 304, the inspection object color determination unit 314 prints the print image data type (first print image data DiB). Image data DiA or second print image data DiB) is determined.

  When the determination result is the first print image data DiA, the inspection target color determination unit 314 notifies the built-in image sensor 200 that the inspection target color is the inspection target.

  In addition, when the determination result is the second print image data DiB, the inspection target color determination unit 314 notifies the built-in image sensor 200 that it is a non-inspection target (not an inspection target).

  The built-in image sensor 200 determines whether or not it is necessary to inspect the image after the image is formed by the printing unit 304 based on this notification, and operates based on the necessity.

  The defect determination unit 312 receives the printed image Dp from the built-in image sensor 200 and performs defect determination.

  At this time, the printed image Dp corresponding to the intermediate printed material Pc printed by the first print image data DiA is determined to be defective.

  On the other hand, the printed image Dp printed by the second print image data DiB so as to be superimposed on the intermediate printed material Pc does not execute the defect determination (inspection exclusion measure).

(Transport control)
As shown in FIG. 4, the sorted first print image data DiA and second print image data DiB are print image data on the same surface, but the printing unit 304 performs print processing at different timings. It is supposed to be executed.

  In the first embodiment, the front / back reversing path 194 (see FIG. 1) of the paper transport unit 308 is applied, and the image forming unit performs image forming processing twice on the same surface.

  More specifically, in the single-sided printing process, an intermediate printed matter Pc that has been printed on one side using yellow, magenta, cyan, and black toners is transferred to the printing unit 304 (transfer position shown in FIG. Return to T) (first lap).

  At this time, since the paper P is reversed, the paper P is conveyed to the downstream side of the built-in image sensor 200, and then the front / back reversing path 194 is applied again to return to the printing unit 304. An image is formed using each toner of silver and silver.

  That is, different conveyance processes (see Table 2) are set for the presence or absence of a special color that is excluded from the inspection by the built-in image sensor 200 and the combination of the single-sided or double-sided printing form.

以下に、第１の実施の形態の作用を説明する。

The operation of the first embodiment will be described below.

  First, an image forming process of the image forming apparatus 10 will be described.

Image data that has been subjected to image processing by the image processing unit 13 is sent to each exposure device 40.
In each exposure device 40, each light beam L is emitted according to image data, and is exposed to each image carrier 18 charged by a scorotron charger, thereby forming an electrostatic latent image.

  The electrostatic latent image formed on the image carrier 18 is developed by the developing device, and the first special color (G), the second special color (S), yellow (Y), magenta (M), and cyan (C). A toner image of each color of black (K) is formed.

As shown in FIG. 1, each color toner image formed on the image carrier 18 of each of the image forming units 16G, 16S, 16Y, 16M, 16C, and 16K has six primary transfer rolls 36G,
Multiple transfer is sequentially performed on the intermediate transfer belt 34 by 36S, 36Y, 36M, 36C, and 36K.

  The color toner images transferred onto the intermediate transfer belt 34 are secondarily transferred onto the paper P conveyed from the paper storage unit 48 by the secondary transfer roll 62. The sheet P on which the toner image has been transferred is conveyed toward the fixing unit 82 provided inside the second housing 10B by the conveyance belt 70.

  Each color toner image on the paper P is fixed on the paper P by being heated and pressurized by the fixing unit 82. Further, the sheet P on which the toner image is fixed is cooled by passing through the cooling unit 110 and then sent to the correction device 140 to correct the curvature generated on the sheet P.

  The paper P whose curvature is corrected is discharged to the discharge unit 196 by the discharge roll 198 after an image defect or the like is detected by the built-in image sensor 200.

  On the other hand, when an image is formed on a non-image surface where no image is formed (in the case of duplex printing), after passing through the built-in image sensor 200, the paper P is reversed by the front / back reversing path 194. Then, the toner image is fed into a conveyance path 60 provided above the sheet storage portion 48, and a toner image is formed on the back surface in the above-described procedure.

  In the image forming apparatus 10 according to the first embodiment, components for forming images of the first special color and the second special color (image forming units 16G and 16S, exposure devices 40G and 40S, toner cartridge 14G). 14S and primary transfer rolls 36G and 36S) are configured to be attachable to the first housing 10A as additional components according to the user's selection.

(Special color inspection necessity determination and transport control)
Next, the built-in image sensor 200 detects a toner density defect, an image defect, an image position defect, and the like of the toner image fixed on the paper P.

  The toner density defect is corrected by reading the toner image with the built-in image sensor 200 and feeding back to the image forming unit with respect to environmental changes and machine differences, part deterioration over time, and part machine differences (factor 1 to factor 3). To do.

  Further, the toner density defect is caused by, for example, converting the image data (RGB) received at the time of image formation into an L * a * b * color space or the like in response to the color conversion error (factor 4). The image is converted into cmyk, which is an image, and there may be a color if it is reproduced during the color conversion process. Therefore, the toner image is read by the built-in image sensor 200, fed back to the image forming unit, and corrected so as to achieve proper color conversion.

  Further, the image defect performs feedback correction for interpolating with surrounding image data, and the image position defect performs feedback correction for changing the image position.

  In the first embodiment, when the print image data includes gold (G) applied as the first special color and silver (S) applied as the second special color, the image processing shown in FIG. The section 300 sorts the first print image data DiA in yellow, magenta, cyan, and black and the second print image data DiB in gold and silver, and determines whether or not the inspection target color determination section 314 is an inspection target. Then, the front / back reversing path 194 (see FIG. 1) of the paper transport unit 308 is applied, and the image forming unit performs image forming processing twice on the same surface.

  FIG. 6 is a flowchart showing a control routine for determining whether or not the inspection target by the built-in image sensor 200 is necessary, transporting the paper P in a transport pattern based on the necessity, and executing print processing and inspection processing. is there.

  In step 350, it is determined whether or not a document image has been accepted. If the determination is negative, this routine ends.

  If an affirmative determination is made in step 350, the process proceeds to step 352 and image analysis is executed. That is, color conversion or the like is performed to generate print image data.

  In the next step 354, the printing form is determined. The printing form is a determination of whether printing is performed on one side of the paper P (single-sided printing) or printing on both sides (double-sided printing).

  In the next step 356, the presence / absence of a special color on each side (of course, one side in the case of single-sided printing) is determined, and the process proceeds to step 358.

  In step 358, it is determined whether or not there is a special color as a result of the determination in step 356. If an affirmative determination is made, the process proceeds to step 360. If a negative determination is made in step 358, the process proceeds to step 364.

  In step 360, the inspection object determination table (Table 1) set for each special color is read, and the process proceeds to step 362 to determine whether or not each special color is inspected by the built-in image sensor 200, and the process proceeds to step 364. .

  In step 364, based on the printing form (single-sided printing, double-sided printing) and the necessity of special color inspection, a transport pattern is selected based on Table 2, and then the process proceeds to step 366, on the basis of the selected transport pattern. The printing process and the inspection process are executed, and this routine ends.

  When the conveyance pattern 1 is selected, since all colors are inspection targets, the normal color printing on the surface → the surface inspection → the discharge process is performed.

  When the transport pattern 2 is selected, there is a special color that is excluded from inspection, so normal color printing on the surface → inspection on the surface → reversal → through → reversal → special color printing → paper discharge.

  When the transport pattern 3 is selected, since all colors are inspection targets, the normal color printing on the front surface → inspection on the front surface → reversal → normal color printing on the back surface → inspection on the back surface → discharge process.

  When the transport pattern 4 is selected, there is a special color excluded from inspection on the front surface, and all colors on the back surface are inspection targets. Therefore, normal color printing on the front surface → inspection on the front surface → reversal → normal color printing on the back surface → reversal → This is the process of special color printing on the front surface, reversal, and paper discharge.

  When the transport pattern 5 is selected, all the colors on the front side are inspected and there are special colors that are excluded from the inspection on the back side, so normal color printing on the front side → front side inspection → reversal → normal color printing on the back side → back side This is the process of inspection → reversal → through → reversal → special color printing on the back side → discharge.

  When the transport pattern 6 is selected, there are special colors that are excluded from the inspection on both the front and back surfaces, so normal color printing on the front surface → inspection on the front surface → reversal → normal color printing on the back surface → inspection on the back surface → reversal → special surface Color printing → reversal → backside special color printing → discharge process.

  In the first embodiment, since the existing front / back reversing path 194 is used, it is necessary to make two turns when performing multiple printing on the same surface.

  Therefore, as a modified example, a new path (multiple printing transport path) for feeding from the paper transport path 194B to the transport path 60 of the first housing 10A may be provided in the front / back reversing path 194 shown in FIG. As a result, the paper P can be turned around without being reversed.

“Second Embodiment”
The second embodiment will be described below. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and description of the configuration is omitted.

  In the first embodiment, a single image forming unit 16 (single printing unit 304) is used, and the paper P is circulated using the front / back reversing path 194 applied to double-sided printing, so that the same surface is provided. Two printing processes were executed.

  In contrast, in the second embodiment, as shown in FIG. 7, the first printing unit 304A for normal color printing is provided on the upstream side of the built-in image sensor 200, and a special print is provided on the downstream side of the built-in image sensor 200. A second printing unit 304B for color printing is provided.

  This eliminates the need for the paper P to circulate in order to perform printing twice on the same surface.

  In the second embodiment, the configuration is the same as that of the first embodiment except for the first printing unit 304A and the second printing unit 304B. However, as a modification of the second embodiment, the first embodiment The two image forming apparatuses 10 applied in this embodiment are arranged (so-called multiple arrangement), normal colors are printed by the upstream image forming apparatus 10, and special colors are printed by the downstream image forming apparatus 10. You may make it print.

L light beam P paper OA optical axis 10 image forming apparatus 10A first housing 10B second housing 13 image signal processing unit 14 (14G, 14S, 14Y, 14M, 14C, 14K) toner cartridge 16 (16G, 16S, 16Y) , 16M, 16C, 16K) Image forming unit 18 (18G, 18S, 18Y, 18M, 18C, 18K) Image carrier 20 Controller 20A CPU
20B ROM
20C RAM
20D I / O port 20E Bus 30 User interface (UI) panel 32 Transfer section 34 Intermediate transfer belt 36 (36G, 36S, 36Y, 36M, 36C, 36K) Primary transfer roll 38 Drive roll 40 (40G, 40S, 40Y, 40M) , 40C, 40K) Exposure device 41 Tension applying roll 42 Opposing roll 44 Winding roll 46 Removal device 48 Paper storage unit 52 Delivery roll 50 Bottom plate 54 Conveyance roll 56 Separation roll 60 Conveyance path 60A First direction change part 60B Second direction change Unit 62 Secondary transfer roll 66 Preliminary path 70 Conveying belt 72 Rolling roll 80 Conveying belt 82 Fixing unit 84 Fixing belt 88 Pressing roll 89 Driving roll 90 Drive roll 100 Control circuit 108 Conveying belt 110 Cooling unit 112 Absorber DESCRIPTION OF SYMBOLS 14 Pressing device 116 Absorption belt 118 Winding roll 120 Drive roll 122 Heat sink 128 Fan 130 Pressing belt 140 Correction device 194 Front / reverse inversion path 194A Branch path 194B Paper conveyance path 194C Front / back inversion path 196 Discharge unit 198 Discharge roll 200 Built-in image sensor 202 Illumination Section 204 CCD sensor 206 Imaging optical system 208 Imaging section 212 Lamp 212A First lamp 212B Second lamp 214 First mirror 216 Second mirror 218 Third mirror 220 Lens 224 (224L, 224S, 224U) Light amount diaphragm section 226 Reference Roll 210 Setting unit 226 Reference roll 228 Detection reference surface 230 Retraction surface 286 Window glass 300 Image processing unit 302 Image forming unit 304 Printing unit 306 Paper feeding unit 308 Paper transport unit 310 Paper discharge unit 312 Defect determination unit 314 Inspection target color determination unit Dg Document image data Di Print image data Pc Intermediate print product Ps Final print product DiA First print image data DiB Second print image data

Claims (4)

Sorting means for sorting the colors when color-converted for image formation according to whether they correspond to preset colors;
Image forming means for forming an image on a recording medium by overlapping each of the colors sorted by the sorting means in a plurality of times; and
An image inspection means for inspecting an image of a color other than the specific color formed on the recording medium before forming an image using the specific color sorted by the sorting means;
An image processing apparatus. As the recording medium conveyance path, a peripheral circuit is provided to return from the downstream side in the recording medium conveyance direction of the image inspection unit to the upstream side in the recording medium conveyance direction of the image forming unit,
The image processing apparatus according to claim 1, wherein an image to be image inspection target is formed first, and an image other than the image inspection target is formed later. The peripheral circuit is an existing conveyance path that reverses the front and back surfaces of the recording medium and sends the recording medium to the image forming unit,
The image processing apparatus according to claim 2, wherein an image is formed for each color sorted by the sorting unit on the same surface of the recording medium by repeating inversion twice. The image forming means is
A first image forming unit disposed on the upstream side in the transport direction of the recording medium with respect to the image inspecting unit and forming an image to be inspected;
The image processing apparatus according to claim 1, further comprising: a second image forming unit that is disposed downstream of the image inspection unit in the conveyance direction of the recording medium and forms an image other than the image inspection target.

Images