JP2021117462A - Image forming apparatus, print control device, image forming method, print control method, and image forming system - Google Patents

Abstract

To divide a plurality of colors of toner into two to transfer to a printing paper based on print data, and even if a toner image Tz transferred subsequently is deviated from a toner image Tz transferred first, make generation of streaks inconspicuous.SOLUTION: An image forming apparatus 1 prints a plurality of colors of toner on a printing paper P based on print data through one or more times of transfer, and comprises: print data receiving means 61 that receives print data including printing paper color information Cp for specifying the color of the printing paper P; and number of times of transfer and transfer color determination means 63 that determines the number of times of transfer and the colors of toner to be used based on the printing paper color information Cp to be received. When the printing paper is in a dark color (for example, K), the number of times of transfer and transfer color determination means determines a dark color (for example, K) for a toner to be transferred last. In addition, the number of times of transfer and transfer color determination means partially (ΔLα) enlarges an image area of the toner to be transferred last.SELECTED DRAWING: Figure 4

Description

The present invention relates to an image forming apparatus that prints using a developer of a plurality of colors.

In recent years, in an image forming apparatus such as a color electrophotographic printer, in addition to cyan (C), magenta (M), yellow (Y) and black (K) process color toners, white (W) or clear is used as a developer. An image forming apparatus using a special color toner has been proposed.
In this image forming apparatus, a W layer is formed by a special color toner to increase the whiteness, and the process color toner is transferred by superimposing the W layer on the W layer to improve the color reproducibility. In this case, if the amount of toner in the W layer due to the special color toner is too large, transfer failure and fixing failure occur due to the excessive amount of toner, and the print quality deteriorates. Therefore, the amount of toner in the W layer is limited to a certain amount. ..

Therefore, there is a case of printing in the one-time fixing mode in which the CMYK layer and the W layer are transferred and fixed at one time, and a case of printing in the double fixing mode in which the CMYK layer and the W layer are transferred and fixed in two times. The technology for adjusting the amount of toner in the W layer is adopted. That is, in the one-time fixing mode, the amount of toner in the W layer is reduced, and in the case of the two-time fixing mode, the amount of toner in the W layer is increased. In this way, the image forming apparatus adjusts the amount of toner in the W layer to suppress deterioration of print quality due to transfer defects and fixing defects caused by an excessive amount of toner, while increasing the whiteness of the W layer to reproduce colors. The properties are improved (see, for example, Japanese Patent Application Laid-Open No. 2015-18120 (Patent Document 1)).

JP 2015-18120

However, in the above-mentioned conventional image forming apparatus, when printing is performed in the fixing mode twice, the transferred image formed the second time is formed on the transferred image formed the first time, so that the position of the second transferred image is changed. If the image is deviated from the first transferred image, a part of the first transferred image appears in a gap or the like, and there is a problem that streaks or the like are generated as a printing result.
The present invention has an object of solving such a problem, and when printing in the fixing mode twice, even if the position of the transferred image formed the second time deviates from the transferred image formed the first time, the printing result is as a result. An object of the present invention is to provide an image forming apparatus that makes streaks and the like inconspicuous and improves print quality.

In order to solve the above problems, the image forming apparatus according to the present invention prints by transferring and fixing a developer of a plurality of colors on a printing medium based on the print data according to the number of transfers at one time or the number of transfers divided into a plurality of times. An image forming apparatus, the print data receiving means for receiving the print data including the print medium color information for specifying the color of the print medium, and the print medium color of the print data received by the print data receiving means. The transfer number transfer color determining means for determining the transfer count and the color of the developer to be used based on the information is provided, and the transfer count transfer color determining means is such that the color of the print medium of the print medium color information is dark. When is, the number of times of transfer is set to a plurality of times, and the color of the developer of the transfer in the last time is determined to be a color close to the color of the print medium in the print medium color information.

According to the present invention, with the above configuration, the transfer color to be transferred last among the plurality of transfers is set to a transfer color close to the print medium color. It is possible to provide an image forming apparatus that improves print quality by making streaks and the like generated by the misalignment of the transferred image inconspicuous even if the position of the image deviates from a desired position.

It is an internal explanatory view of the image forming apparatus which concerns on 1st Embodiment. It is explanatory drawing of the image formation unit and the transfer part which concerns on 1st Embodiment. It is a block diagram of the image formation system which concerns on 1st Embodiment. It is a main part functional block of an image forming apparatus and a general-purpose terminal which concerns on 1st Embodiment. It is a flowchart of the image formation system which concerns on 1st Embodiment. It is a screen view of the application setting which concerns on 1st Embodiment. It is a screen view which sets the print paper color information Cp which concerns on 1st Embodiment. It is a screen view which sets the white toner use range information Rwt which concerns on 1st Embodiment. It is explanatory drawing of the transfer number transfer color determination table which concerns on 1st Embodiment. It is a flowchart which determines the transfer count and transfer color which concerns on 1st Embodiment. It is explanatory drawing of the transfer image formed by the image forming apparatus which concerns on 1st Embodiment. It is a top view of the transfer image formed by the image forming apparatus which concerns on 1st Embodiment.

(First Embodiment)
The configuration of the first embodiment, which is the best mode for carrying out the present invention, will be described below. In the drawings, the elements common to each drawing are designated by the same reference numerals. FIG. 1 is an internal explanatory view of an image forming apparatus according to the first embodiment. Based on the print data, the image forming apparatus 1 transfers the toner Tn (see FIG. 2) as a developer of a plurality of colors to the printing paper P as a printing medium by the number of transfers once or the number of transfers divided into two. It is fixed and printed.
As shown in FIG. 1, the image forming apparatus 1 includes a feeding unit 7, an image forming unit 8, and an discharging unit 12 surrounded by a broken line. Further, the image forming apparatus 1 includes a paper feed tray 6, a transfer unit 9 having a transfer unit 10, a fixing device 11, and an operation display unit 14. Hereinafter, in FIG. 1, the right side of the paper surface is referred to as “the front side of the device”, and the left side of the paper surface is referred to as “the back side of the device”.

The paper feed tray 6 arranged at the bottom of the apparatus is a tray for stacking and accommodating printing paper P. When printing is started, the printing paper P stacked on the paper feed tray 6 is fed one by one from the upper side by the paper feed roller 15 of the paper feed unit 7 in the direction indicated by the arrow A, and further in the direction indicated by the arrow D. Is transported to the transfer unit 10.
In order to control the transfer of the printing paper P after the paper is fed, the paper feed unit 7 is provided with the paper feed transfer rollers 16 and 17 and the paper feed detection sensor in the transfer path from the paper feed roller 15 to the image forming unit 8. 19 and the timing detection sensor 20 are arranged. The paper feed detection sensor 19 is a sensor that detects the conveyed state of the printing paper P, and the timing detection sensor 20 is a sensor for adjusting the printing timing.

The image forming unit 8 arranges five image forming units 18W, 18C, 18M, 18Y and 18K in order from the front side of the device toward the back side of the device. The plurality of image forming units 18W, 18C, 18M, 18Y and 18K are tonered by toner Tn as a developer of white (W), cyan (C), magenta (M), yellow (Y) and black (K), respectively. Form an image. Hereinafter, the image forming units 18W, 18C, 18M, 18Y and 18K are collectively referred to as "image forming unit 18".
The image forming apparatus 1 disposes the transfer unit 9 in the lower portion thereof facing the image forming unit 8. The transfer unit 9 is composed of a transfer unit 10, a primary transfer roller 37 for each image forming unit 18, an intermediate transfer belt 38, a belt drive roller 22, and driven rollers 23 and 24. The transfer unit 10 is composed of a driven roller 25 and a transfer roller 26 that performs secondary transfer. The intermediate transfer belt 38 is stretched by the belt drive roller 22 and the driven rollers 23 to 25, and is rotated in the direction indicated by the arrow E (clockwise direction) by the drive of the belt drive roller 22.

The toner image formed by the image forming unit 8 is primarily transferred by the primary transfer roller 37 onto the rotating intermediate transfer belt 38, and the primary transfer image Ts shown in FIG. 2 is formed later. The primary transfer image Ts formed on the intermediate transfer belt 38 is secondarily transferred by the transfer unit 10 to the printing paper P conveyed in the direction indicated by the arrow D, and the transfer image Tz shown later in FIG. 2 is formed. do.
The fuser 11 is composed of a pressurizing roller 11a and a heating roller 11b having a heating portion inside. The fixing device 11 presses the printing paper P on which the transfer image Tz is formed by the pressure roller 11a and heats it by the heating roller 11b to fix it on the printing paper P.
The image forming apparatus 1 includes a return transfer mechanism 28 and a front / back inversion mechanism 29 in the lower part of the fixing device 11. The return transfer mechanism 28 includes return transfer rollers 27, 71, and 72, and conveys the printing paper P when performing the second transfer and fixing following the first transfer and fixing. The front-back reversing mechanism 29 includes a front-back reversing transport roller pair 73, and transports the printing paper P when printing on the back surface following printing on the front surface when performing double-sided printing.

The discharge unit 12 conveys the transferred and fixed printing paper P in the direction indicated by the arrow F, discharges it to the discharge stacker 13 at the upper part of the apparatus, and loads the printing paper P in order. For this purpose, the discharge unit 12 disposes the discharge transport rollers 75 to 77 in the transport path from the fixing device 11 to the discharge stacker 13. The discharge unit 12 is further provided with a discharge detection sensor 21 that detects the discharge state of the printing paper P and the like.
The operation display unit 14 is provided on the upper portion on the front side of the device so that the user can easily operate the operation display unit 14. The operation display unit 14 is configured by, for example, mounting a transparent touch panel that functions as an operation unit on an LCD (Liquid Crystal Display) that functions as a display unit. The user can confirm the operation guidance and give a printing instruction such as starting printing on the operation display unit 14.

(Structure of image forming unit)
Next, the configurations of the image forming unit 18 and the transfer unit 10 according to the first embodiment will be described. FIG. 2 is an explanatory diagram of an image forming unit and a transfer unit according to the first embodiment. Note that FIG. 2A shows the internal configuration of the image forming unit 18, and FIG. 2B shows the configuration of the transfer unit 10. The image forming units 18W, 18C, 18M, 18Y and 18K have the same configuration as that shown in FIG. 2A.

As shown in FIG. 2A, the image forming unit 18 arranges the LED head 31 so as to face the photoconductor drum 30, and causes the LED head 31 to form an electrostatic latent image on the photoconductor drum 30. Further, the image forming unit 18 includes a toner cartridge 39 detachably arranged with respect to the image forming unit 18, and accommodates toner Tn of each color in each toner cartridge 39.
Further, the image forming unit 18 includes a developing roller 34, a supply roller 35, and a developing blade 36. The developing roller 34 is arranged adjacent to the photoconductor drum 30 and forms a toner image on the photoconductor drum 30.

That is, the developing roller 34 rotates with the photoconductor drum 30 in the direction indicated by the arrow U, and develops by adhering the toner Tn to the electrostatic latent image formed on the photoconductor drum 30. The photoconductor drum 30 is composed of a charging member, and is rotated in the direction indicated by the arrow V by the driving force transmitted later from the motor driving unit 54 shown in FIG.
The supply roller 35 supplies the toner Tn to the developing roller 34. The supply roller 35 is arranged in contact with the developing roller 34, and rotates in the same direction as the developing roller 34 and at a different peripheral speed by a predetermined speed. The supply roller 35 rotates in the direction indicated by the arrow T by the driving force transmitted later from the motor driving unit 54 shown in FIG. The developing blade 36 is arranged so that its tip is in contact with the developing roller 34, and regulates the amount of toner on the developing roller 34.

Further, the image forming unit 18 includes a charging roller 32 and a cleaning blade 33. The charging roller 32 is a roller that uniformly charges the surface of the photoconductor drum 30 to a predetermined charging voltage. The charging roller 32 is rotatably supported so as to rotate with the photoconductor drum 30 in the direction indicated by the arrow W. Further, the cleaning blade 33 is arranged with its tip abutting against the photoconductor drum 30 at a predetermined pressure, and scrapes off the toner Tn remaining on the surface of the photoconductor drum 30 after the primary transfer to the intermediate transfer belt 38. ..
The image forming unit 8 shown in FIG. 1 is composed of the image forming units 18W, 18C, 18M, 18Y and 18K having the above configurations. The image forming unit 8 sequentially superimposes the toner images formed by each image forming unit 18 on the intermediate transfer belt 38 orbiting in the direction indicated by the arrow E (clockwise direction on the paper) by the primary transfer rollers 37 for primary transfer. , A primary transfer image Ts is formed.

On the other hand, as shown in FIG. 2B, the transfer unit 10 is composed of a driven roller 25 that rotates in the direction indicated by arrow N and a transfer roller 26 that rotates in the direction indicated by arrow Q.
The transfer unit 10 sandwiches the printing paper P conveyed in the direction indicated by the arrow D by the transfer roller 26 and the driven roller 25 to which a predetermined transfer voltage is applied later by the power supply unit 55 shown in FIG. It is conveyed to the fuser 11 on the back side of the device.
In this way, the transfer unit 10 secondarily transfers the primary transfer image Ts formed on the intermediate transfer belt 38 by the image forming unit 18 onto the printing paper P to form the transfer image Tz.

(Configuration of image formation system)
Next, the configuration of the image forming system 2 will be described. FIG. 3 is a block diagram of an image forming system according to the first embodiment. The image forming system 2 includes an image forming apparatus 1 and a general-purpose terminal 3 as a higher-level device, and prints by the image forming apparatus 1 based on print data transmitted from the general-purpose terminal 3.
As shown in FIG. 3, the image forming system 2 is configured to connect the general-purpose terminal 3 and the image forming apparatus 1 by the network 4. The network 4 is composed of a wired interface by LAN (Local Area Network). The network 4 may be a wireless interface by wireless LAN or a wired interface by USB (Universal Serial Bus).

The general-purpose terminal 3 is configured by, for example, a PC (Personal Computer), generates print data of image data displayed, created, or edited by a user, and transmits the print data to the image forming apparatus 1. For this purpose, the general-purpose terminal 3 includes a terminal control unit 40, a display device 41, an input device 42, a terminal communication unit 43, and a terminal storage unit 44. The terminal control unit 40 is composed of a microprocessor or the like, and controls each of the above units. The display device 41 is composed of an LCD (Liquid Crystal Display) or the like. The input device 42 is configured by loading a transparent touch panel that functions as an operation unit on the LCD. The input device 42 may be configured so that a keyboard, a mouse, and the like can be used together. The terminal communication unit 43 controls an interface that connects to the communication unit 53 of the image forming apparatus 1 via the network 4. The terminal storage unit 44 stores image data and the like created by the user.

The image forming apparatus 1 prints on the printing paper P based on the print data transmitted from the general-purpose terminal 3. For this purpose, the image forming apparatus 1 includes a control unit 50, an operation display unit 14, a storage unit 51, a print control unit 52, a communication unit 53, a motor drive unit 54, and a power supply unit 55. The control unit 50 is composed of a microprocessor or the like, and controls each unit. The operation display unit 14 is composed of an operation display unit 14 arranged on the upper portion of the image forming apparatus 1 shown in FIG. 1 on the front side of the apparatus. The storage unit 51 stores the transfer number transfer color determination table 68 and the like, which will be shown later in FIG.

The print control unit 52 controls the drive of a motor or the like (not shown) by the motor drive unit 54, and controls the rotational drive of the supply roller 35 and the photoconductor drum 30 and the like. Further, the print control unit 52 controls the rotation drive of the paper feed roller 15, the paper feed transfer roller pairs 16 and 17, the belt drive roller 22, and the like by the motor drive unit 54. In addition, the print control unit 52 controls the charging voltage of the charging roller 32, the developing voltage of the developing roller 34, the primary transfer voltage of the primary transfer roller 37, and the transfer voltage of the transfer roller 26 by the power supply unit 55. The communication unit 53 controls an interface that connects to the general-purpose terminal 3 via the network 4.

Next, the main functional blocks of the image forming apparatus 1 and the general-purpose terminal 3 will be described. FIG. 4 is a main functional block of the image forming apparatus and the general-purpose terminal according to the first embodiment. First, the main functional blocks of the general-purpose terminal 3 will be described. As shown in FIG. 4, the main part of the general-purpose terminal 3 is composed of an application 46 and a printer driver 47 as a print control device. As shown in FIG. 4, each of these units may be configured to function by the terminal control unit 40, or may be configured to function separately from the terminal control unit 40.
The application 46 creates, displays, or edits image data to be printed by the user. Further, the application 46 selects the printer driver 47 of the image forming apparatus 1 to be printed by the user. In addition, the application 46 outputs the image data displayed by the user to the printer driver 47.

The printer driver 47 uses the print paper color information Cp as the print medium color information for specifying the color of the print medium, which will be described later in FIG. 9, and the special color developer on the print paper in which the image data input from the application 46 is used. The print data is generated by adding each information of the white toner usage range information Rwt as the special color developer usage range information for specifying the range of. For this purpose, the printer driver 47 includes a print paper color setting unit 48 as a print medium color setting means for setting each of the above information, and a white toner use range setting unit 49 as a spot color developer use range setting means. The image data input from the application 46 may be converted into image data in the printer description language format.
Further, the printer driver 47 transmits the generated print data to the image forming apparatus 1 selected by the user via the network 4.

The print paper color setting unit 48 sets the print paper color information Cp that specifies the print paper color. The print paper color setting unit 48 sets the print paper color based on the user's selection on the print paper color setting screen G10 shown later in FIG. 7.
The white toner use range setting unit 49 sets the white toner use range information Rwt that specifies the range on the printing paper that uses the white toner as the special color developer. The white toner use range setting unit 49 sets the range in which the white toner is used based on the user's selection on the white toner use range setting screen G20 shown later in FIG.

Next, the main functional block of the image forming apparatus 1 will be described. As shown in FIG. 4, the main parts of the image forming apparatus 1 are a print data receiving unit 61, a color conversion unit 62, a transfer count transfer color determination unit 63, a white amount adjustment processing unit 64, an image area enlargement unit 65, and a halftone. It is composed of a processing unit 66 and a printing unit 67. As shown in FIG. 4, each of these units may be configured to function by the control unit 50, or may be configured to function separately from the control unit 50.
The print data receiving unit 61 as the print data receiving means receives the print data including the print paper color information Cp for specifying the print paper color and the white toner use range information Rwt for specifying the range in which the white toner is used. It is a thing.

That is, the print data receiving unit 61 receives the print data from the printer driver 47 of the general-purpose terminal 3 and outputs the image data and the white toner usage range information Rwt to the color conversion unit 62. The image data is, for example, image data of 256 gradations of each RGB color. Further, the print data receiving unit 61 outputs the print paper color information Cp and the white toner usage range information Rwt to the transfer number transfer color determination unit 63.

The color conversion unit 62 converts the image data input from the print data receiving unit 61 into WCMYK image data having 256 gradations of each WCMYK color, which is the color space of the image forming apparatus 1. In this color conversion, for example, the image data of 256 gradations of each RGB color is converted into the WCMYK image data of 256 gradations of each color of WCMYK by a conversion method using a color conversion table which is a known technique. The color conversion table is, for example, a look-up table by three-dimensional display in which the relationship between the RGB color space and the WCMYK color space is described in consideration of the color reproduction characteristics of the image forming apparatus 1. The color conversion unit 62 outputs the WCMYK image data converted by the color conversion table to the white amount adjustment processing unit 64.

The transfer count transfer color determination unit 63 as the transfer count transfer color determination means determines the transfer count and the transfer color based on the print paper color information Cp and the white toner usage range information Rwt input from the print data receiving unit 61. ..
That is, the transfer count transfer color determination unit 63 determines the number of transfers and fixings (hereinafter, referred to as "transfer count") indicating whether to print in the one-time fixing mode or the two-time fixing mode. Here, when the number of transfers is one, the one-time fixing mode is the W layer of a spot color developer such as white (W) and cyan (C), magenta (M), yellow (Y), and black (K). This mode transfers and fixes the CMYK layer of the process color toner at one time. The double fixing mode when the number of transfers is two is a mode in which the W layer and the CMYK layer are transferred and fixed in two steps.

Further, when the number of transfers is two, the transfer number transfer color determination unit 63 determines the toner color as the transfer color used at the time of the first transfer and fixing of the plurality of toners, and the final transfer and the second transfer. Determine the toner color as the transfer color to be used for fixing. On the other hand, when the number of transfers is one, all WCMYK colors are used as the transfer colors.
Specifically, for example, the transfer count transfer color determination unit 63 may use the white toner only in the portion where the image is formed by the white toner use range information Rwt as in step S37 shown later in FIG. When the printing paper color information Cp is not light, that is, when it is a dark color system, the number of transfers is set to 2. Further, the transfer number transfer color determination unit 63 sets the transfer color in the first transfer as the first transfer to a color other than the second transfer color, and sets the transfer color in the second transfer as the final transfer to the printing paper color. The color should be close to.
The transfer count transfer color determination unit 63 outputs the determined transfer count and transfer color to the white amount adjustment processing unit 64, the image area enlargement unit 65, and the printing unit 67.

The white amount adjustment processing unit 64 determines the total thickness of the WCMYK toner based on the WCMYK image data input from the color conversion unit 62 and the number of transfers input from the transfer number transfer color determination unit 63. Here, the total toner thickness is the total thickness required to reproduce colors using the WCMYK toner, and refers to the total thickness of the toner that can be fixed at one time by printing by an electrophotographic method. The total toner thickness is expressed as a percentage based on the amount of white toner required to shield the color of the printing paper, that is, the W layer thickness as a reference (100%).
The white amount adjustment processing unit 64 generates white amount adjustment WCMYK image data in which the amount of white toner is adjusted based on the determined total thickness of WCMYK. The total thickness of the WCMYK toner is made larger in the double fixing mode than in the single fixing mode. For example, in the case of the single fixing mode, the total thickness of the WCMYK toner is 300%, and in the case of the double fixing mode, it is 340%.

The total thickness of the WCMYK toner is determined as follows. That is, the first condition is that the total thickness that can be transferred and fixed at one time is 300%. The second condition is that the total CMYK thickness required to reproduce colors using CMYK toner is 240%. Further, the third condition is that the amount of white toner required to shield the color of the printing paper P is 100%. Then, the order of superiority is the first condition> the second condition> the third condition.
Under the above conditions, in the case of the one-time fixing mode, the total thickness of the WCMYK toner is 300% from the first condition. Further, since the total thickness of CMYK needs to be 240% from the second condition, the third condition is not satisfied, but the amount of white toner is 300% -240% = 60%.
On the other hand, in the case of the double fixing mode, even if the total CMYK thickness is 240% from the second condition and the amount of white toner is 100% from the third condition, the first condition is satisfied. Is 240% + 100% = 340%.

The white amount adjustment processing unit 64 adjusts the amount of white toner so that the total thickness of the WCMYK toner of the WCMYK image data input from the color conversion unit 62 is equal to or less than the total thickness of the WCMYK toner determined based on the number of transfers. That is, when the total thickness of the WCMYK toner exceeds the total thickness of the WCMYK toner determined based on the number of transfers, the white amount adjusting processing unit 64 reduces the excess amount from the amount of white toner to be equal to or less than the total thickness of the WCMYK toner. Adjust the amount of white toner so as to.
The white amount adjustment processing unit 64 adjusts the amount of white toner based on the total thickness of WCMYK determined based on the number of transfers as described above, and outputs the generated white amount adjustment WCMYK image data to the image area enlargement unit 65. .. The amount of toner is controlled by thinning out the dots in the halftone processing unit 66.

The image area enlargement unit 65 as the image area enlargement means extends the image area of the second transfer color as the last transfer of the plurality of transfers by a predetermined length (later shown in FIGS. 11B and 12C). ) Shows ΔLα). That is, the image area enlargement unit 65 enlarges and enlarges the image area of the second transfer color input from the transfer number transfer color determination unit 63 in the white amount adjustment WCMYK image data input from the white amount adjustment processing unit 64. Generate WCMYK image data. To enlarge the image region, a known image edge detection technique is used to detect the edge of the image region of the transferred color for the second time, and the detected edge portion is enlarged by a predetermined length (ΔLα).
When the number of transfers is 2, the image area enlargement unit 65 uses the enlarged WCMYK image data generated as described above as WCMYK image data, and when the number of transfers is 1, the WCMYK image data is directly transferred to the halftone processing unit 66. Output.

The halftone processing unit 66 binarizes the WCMYK image data input from the image area expansion unit 65 by halftone processing, and generates WCMYK binarized image data of two gradations of each color of WCMYK. The halftone processing unit 66 outputs the generated WCMYK binarized image data to the printing unit 67. The binarization process is performed by, for example, the dither method, which is a known technique.
The printing unit 67 as a printing means prints the WCMYK binarized image data input from the halftone processing unit 66 on the printing paper P based on the transfer count and the transfer color input from the transfer count transfer color determination unit 63. ..

(Operation of image formation system)
With the above configuration, the image forming system 2 according to the first embodiment operates as follows. FIG. 5 is a flowchart of an image forming system according to the first embodiment.
First, the user activates the general-purpose terminal 3 and then activates the application 46 of the general-purpose terminal 3 shown in FIG. After that, the user selects the image data to be printed in the started application 46 and starts printing. The following display on the general-purpose terminal 3 is performed by the display device 41 shown in FIG. 3, and the setting operation on the general-purpose terminal 3 by the user is performed by the input device 42 shown in FIG.

Step S11: When printing is started by the user, the terminal control unit 40 (see FIG. 3) of the general-purpose terminal 3 displays the application setting screen G01 shown in FIG. 6 below by the application 46, and accepts the application settings related to printing. .. For example, the terminal control unit 40 of the general-purpose terminal 3 accepts the selection of the printer driver 47 of the image forming apparatus 1 used for printing and the print settings related to printing such as the print range and the number of copies to be printed as application settings by the application 46. The application settings are composed of setting contents common to each printer driver 47.

FIG. 6 is a screen view of application settings according to the first embodiment. As shown in FIG. 6, the terminal control unit 40 of the general-purpose terminal 3 displays the printer name setting field 102, the print range setting field 103, and the number of prints setting field 104 as the application setting screen G01. In addition, the terminal control unit 40 of the general-purpose terminal 3 displays an operation guidance 101, an OK button 105, and a cancel button 106 that prompt the user to specify a printing method.
The printer name setting field 102 is a field for selecting the printer driver 47 of the image forming apparatus 1 used for printing, and the selectable printer driver 47 is displayed by the printer name or the like by the pull-down menu. The print range setting field 103 is a field for setting which page of the image data of the plurality of pages to print the image data. The number of copies setting field 104 is a field for setting the number of copies to be printed.

The OK button 105 is a button to be pressed when the setting contents are maintained and the next printer driver setting is performed. The cancel button 106 is a button to be pressed when the setting contents are discarded and printing is finished. The user selects the printer driver 47, sets the print range, and the like on the application setting screen G01, and presses the OK button 105.
Returning to FIG. 5, when the OK button 105 is pressed by the user, the terminal control unit 40 of the general-purpose terminal 3 stores the contents received as the application settings in the terminal storage unit 44 (see FIG. 3), and the next printer. Proceed to driver settings. The following printer driver settings are composed of unique setting contents for each printer driver 47.

Step S12 (print medium color setting step): The terminal control unit 40 of the general-purpose terminal 3 uses the print paper color setting unit 48 (see FIG. 4) of the printer driver 47 to set the print paper color by the user as one of the printer driver settings. Set the print paper color information Cp to specify.
FIG. 7 is a screen view for setting the print paper color information Cp according to the first embodiment. As shown in FIG. 7, the terminal control unit 40 of the general-purpose terminal 3 serves as a printing paper color setting screen G10 with six hues of red (R), yellow (Y), green (G), cyan (C), and blue ( The selection buttons for B) and magenta (M) are displayed, for example, in three levels of brightness. That is, the selection button is displayed as a dark color selection button row 112, a middle color selection button row 113, and a light color selection button row 114.

Further, the terminal control unit 40 of the general-purpose terminal 3 displays the white button 115 and the black button 116. These selection buttons are displayed in color. In this way, the print paper color setting screen G10 is displayed so that it can be selected and set separately for dark color / intermediate color (Dark / Middle) and black dark color system and light color (Light) and white light color system.
In addition, the terminal control unit 40 of the general-purpose terminal 3 has an operation guidance 111 that prompts the user to select a color closest to the color of the printing paper P, and an OK button that is pressed when the setting contents are maintained and the next setting is performed. Display 117 and the back button 118 to be pressed when returning to the application setting screen G01 after discarding the setting contents.

Returning to step S12 of FIG. 5, on the print paper color setting screen G10, when the user presses the color selection button closest to the color of the print paper P and the OK button 117 is pressed, the terminal control of the general-purpose terminal 3 is performed. In the unit 40, the color of the pressed selection button is the color of the printing paper. The terminal control unit 40 of the general-purpose terminal 3 sets the print paper color as the print paper color information Cp by the printer driver 47 and stores it in the terminal storage unit 44 (see FIG. 3).
The printing paper colors are 6 hues of red (R), yellow (Y), green (G), cyan (C), blue (B) and magenta (M), and 3 levels of brightness dark color (Dark). It is represented by a neutral color (Middle) and a light color (Light), and is used as printing paper color information Cp. Alternatively, the print paper color may be represented by a button number or the like that identifies each selection button, and may be used as the print paper color information Cp.

Step S13 (Special Color Developer Usage Range Setting Step): Next, the terminal control unit 40 of the general-purpose terminal 3 is set as another printer driver setting by the white toner usage range setting unit 49 (see FIG. 4) of the printer driver 47. , Set the white toner usage range information Rwt that specifies the range in which the white toner is used by the user.
FIG. 8 is a screen view for setting the white toner usage range information Rwt according to the first embodiment. As shown in FIG. 8, the terminal control unit 40 of the general-purpose terminal 3 provides an operation guidance 121 and radio buttons 122 to 124 as the white toner usage range setting screen G20 to prompt the user to set the white toner usage range. indicate.

Radio button 122 is a button selected by the user when white toner is not used. When printing on white printing paper P such as plain paper, white toner is not normally used, so the user selects this radio button 122.
The radio button 123 is a button selected by the user when white toner is used for the entire printing paper. The radio button 124 is a button to be selected when white toner is used only in the portion where the image is formed (hereinafter, referred to as “only the image portion”). When printing on dark / neutral (Dark / Middle) and black dark printing paper P, white toner is usually used to shield the printing paper color, so that the user can use the radio button 123 or the radio button. Select 124. The radio button 122 to the radio button 124 are displayed so that any one of them is selected.

Further, the terminal control unit 40 of the general-purpose terminal 3 presses an OK button 125 to be pressed when the setting contents are maintained and printing is continued, and a back button 126 to be pressed when returning to the application setting screen G01 after discarding the setting contents. indicate. On the white toner usage range setting screen G20, the user selects one of the radio button 122 to the radio button 124 and presses the OK button 125 to input the white toner usage range.

Returning to step S13 of FIG. 5, when the OK button 125 is pressed by the user, the terminal control unit 40 of the general-purpose terminal 3 sets the white toner usage range input by the user by the printer driver 47 to the white toner usage range information. It is set as Rwt and stored in the terminal storage unit 44 (see FIG. 3).
The print paper color setting screen G10 and the white toner usage range setting screen G20 may display property buttons (not shown) on the application setting screen G01, and display them in order when the property buttons are pressed by the user. ..

Step S14 (Print Data Generation Step): The terminal control unit 40 of the general-purpose terminal 3 converts the image data selected by the user in the application 46 into a printer description language format that can be interpreted by the image forming apparatus 1 by the printer driver 47. And generate print data. At this time, the terminal control unit 40 of the general-purpose terminal 3 reads out the print paper color information Cp and the white toner usage range information Rwt set in steps S12 and S13 and stored in the terminal storage unit 44 by the printer driver 47, and print data. To add to.
Step S15 (print data transmission step): The printer driver 47 transmits the print data generated in step S14 by the terminal communication unit 43 (see FIG. 3) under the control of the terminal control unit 40 of the general-purpose terminal 3 to the network 4. Is transmitted to the image forming apparatus 1 via.

Step S21 (print data receiving step): The control unit 50 (see FIG. 3) of the image forming apparatus 1 receives the print data receiving unit 61 (see FIG. 4) from the printer driver 47 of the general-purpose terminal 3 via the network 4. Receive print data. That is, the control unit 50 of the image forming apparatus 1 receives the print data including the print paper color information Cp for specifying the print paper color and the white toner use range information Rwt for specifying the range in which the white toner is used.
The control unit 50 of the image forming apparatus 1 outputs the image data included in the received print data and the white toner usage range information Rwt to the color conversion unit 62 by the print data receiving unit 61. At the same time, the control unit 50 of the image forming apparatus 1 outputs the print paper color information Cp and the white toner usage range information Rwt included in the received print data to the transfer number transfer color determination unit 63.

Step S22: The control unit 50 of the image forming apparatus 1 converts the image data input from the print data receiving unit 61 into WCMYK image data by the color conversion unit 62 (see FIG. 4). At this time, the control unit 50 of the image forming apparatus 1 determines the total thickness of the WCMYK toner based on the white toner usage range information Rwt. That is, the control unit 50 of the image forming apparatus 1 sets the total thickness of the CMYK toner to a maximum of 240% by the color conversion unit 62. Further, the control unit 50 of the image forming apparatus 1 determines the amount of white toner by the color conversion unit 62 based on the white toner usage range information Rwt. That is, the control unit 50 of the image forming apparatus 1 sets the amount of white toner to 100% in the region where white toner is used, and sets the amount of white toner to 0% in the region where white toner is not used.

Step S23 (Transfer Count Transfer Color Determination Step): The control unit 50 of the image forming apparatus 1 receives the white toner usage range information Rwt input from the print data receiving unit 61 by the transfer count transfer color determination unit 63 (see FIG. 4). And the number of transfers is determined based on the printing paper color information Cp. Further, the control unit 50 of the image forming apparatus 1 determines the transfer color by the transfer number transfer color determination unit 63 based on the white toner usage range information Rwt and the printing paper color information Cp. The transfer count and transfer color are determined later by using the transfer count transfer color determination table 68 shown in FIG. 9 and by the transfer count and transfer color determination operation shown in FIG.

Step S24: Next, the control unit 50 of the image forming apparatus 1 determines the total WCMYK thickness based on the number of transfers input from the transfer number transfer color determination unit 63 by the white amount adjustment processing unit 64 (see FIG. 4). do. Further, the control unit 50 of the image forming apparatus 1 generates white amount adjustment WCMYK image data in which the amount of white toner is adjusted based on the determined WCMYK total thickness by the white amount adjustment processing unit 64.

For example, the control unit 50 of the image forming apparatus 1 sets the total thickness of WCMYK to 340% and adjusts the amount of white toner so as to be equal to or less than the total thickness of WCMYK when the number of transfers is two by the white amount adjusting processing unit 64. A white amount-adjusted WCMYK image is generated.
On the other hand, when the number of transfers is one, the control unit 50 of the image forming apparatus 1 adjusts the total thickness of WCMYK to 300% by the white amount adjusting processing unit 64, and adjusts the amount of white toner so as to have the total thickness of WCMYK. White amount adjustment WCMYK image is generated.
After that, the control unit 50 of the image forming apparatus 1 outputs the generated white amount adjustment WCMYK image data to the image area enlargement unit 65 by the white amount adjustment processing unit 64.

Step S25 (image area enlargement step): When the number of transfers is two, the control unit 50 of the image forming apparatus 1 determines the image area of the second transfer color by the image area enlargement unit 65 (see FIG. 4). (See FIG. 11B) Enlarged magnified WCMYK image data is generated. On the other hand, when the number of transfers is one, the control unit 50 of the image forming apparatus 1 does not expand the image area by the image area expanding unit 65 because a large positional deviation does not occur.
As described above, the enlarged WCMYK image data is generated based on the white amount adjustment WCMYK image data input from the white amount adjustment processing unit 64 and the transfer number and transfer color input from the transfer number transfer color determination unit 63.

For example, when the number of transfers is two and the second transfer color is black (K), the control unit 50 of the image forming apparatus 1 uses the image area enlargement unit 65 to adjust the amount of white (K) of the white amount adjustment WCMYK image data. Enlarged WCMYK image data is generated by enlarging the image area of No. 1 by ΔLα by a predetermined length. On the other hand, when the number of transfers is one, the control unit 50 of the image forming apparatus 1 does not enlarge the black (K) image area by the image area enlargement unit 65.
When the number of transfers is two, the control unit 50 of the image forming apparatus 1 outputs the enlarged WCMYK image data generated as described above to the halftone processing unit 66 by the image area enlargement unit 65, and the number of transfers is once. In the case of, the WCMYK image data is output to the halftone processing unit 66. The enlarged WCMYK image data and WCMYK image data output to the halftone processing unit 66 are, for example, 256 gradations of each WCMYK color.

Step S26: The control unit 50 of the image forming apparatus 1 binarizes the enlarged WCMYK image data or WCMYK image data input from the image area expansion unit 65 by the halftone processing unit 66 (see FIG. 4), and the WCMYK colors 2 Generates WCMYK binarized image data of gradation. The control unit 50 of the image forming apparatus 1 outputs the generated WCMYK binarized image data to the printing unit 67 by the halftone processing unit 66.

Step S27 (Printing Step): The control unit 50 of the image forming apparatus 1 is input from the halftone processing unit 66 by the printing unit 67 based on the transfer count and the transfer color input from the transfer count transfer color determination unit 63. The WCMYK binarized image data is printed on the printing paper P.
For example, when the number of transfers is "2" and the second transfer color is "black (K)", the control unit 50 of the image forming apparatus 1 transfers the WCMY layer to the first time by the printing unit 67. And fixed, and black (K) is transferred and fixed a second time, and printed on printing paper P. On the other hand, when the number of transfers is "1 time", the control unit 50 of the image forming apparatus 1 transfers and fixes the WCMYK layer at one time by the printing unit 67, and prints on the printing paper P.

Next, the operation of determining the number of transfers and the transfer color according to the first embodiment in step S23 shown in FIG. 5 will be described. First, the transfer count transfer color determination table 68 for reference when the control unit 50 of the image forming apparatus 1 determines the transfer count and the transfer color will be described.
FIG. 9 is an explanatory diagram of a transfer number transfer color determination table according to the first embodiment. The transfer number transfer color determination table 68 is a table for reference when determining the transfer number and transfer color from the white toner usage range information Rwt and the printing paper color information Cp, and is stored in advance in the storage unit 51 shown in FIG. do. In FIG. 9, white is represented by "W", cyan is represented by "C", magenta is represented by "M", yellow is represented by "Y", and black is represented by "K".

As shown in FIG. 9, the transfer count transfer color determination table 68 is described separately in the “not used” column 131, the “whole printing paper” column 132, and the “image portion only” column 133 according to the white toner usage range information Rwt. Will be done. These correspond to the radio button 122, the radio button 123, and the radio button 124 for the user to set the white toner usage range from the white toner usage range setting screen G20 shown in FIG.

The "not used" column 131 describes the number of transfers and the transferred color to be referred to when the white toner use range information Rwt is "not used", that is, when the user sets that the white toner is not used. In the "not used" column 131, the number of transfers is one and the transfer color is described as "CMYK" regardless of the print paper color specified by the print paper color information Cp.
The "whole printing paper" column 132 describes the number of transfers and the transfer color to be referred to when the white toner usage range information Rwt is "whole printing paper", that is, when the user sets to use white toner for the entire printing paper. Will be done. In the "whole printing paper" column 132, regardless of the printing paper color specified by the printing paper color information Cp, the number of transfers is set to 2, the first transfer color is set to "W", and the second transfer color is set to "W". It is described as "CMYK".

The "image portion only" column 133 refers to the number of transfers and the number of transfers to be referred to when the white toner usage range information Rwt is "image portion only", that is, when the user sets to use the white toner only in the portion where the image is formed. The transfer color is described.
In the "image portion only" column 133, the description is made in correspondence with the color of the selection button displayed on the print paper color setting screen G10 shown in FIG. 7 set by the user. That is, the "image portion only" column 133 is divided into a dark color / intermediate color (Dark / Middle) column 141, a black (K) column 142, a light color (Light) column 143, and a white (W) column 144, and the transfer color is described. Will be done. In other words, the "image portion only" column 133 is described separately for a dark color system of dark color / intermediate color (Dark / Middle) and black (K) and a light color system of light color (Light) and white (W). ..

In the dark / middle color (Dark / Middle) column 141, the specific colors are red (R), yellow (Y), green (G), cyan (C), blue (B), or magenta (M). The transfer color is described separately. That is, in the dark / middle color (Dark / Middle) column 141, the number of transfers is two, the first transfer color is other than the second transfer color, and the second transfer color is a color close to the printing paper color.

For example, when the printing paper color is red (R), the first transfer color is described as "WCK" other than the second transfer color "MY", and the printing paper color is superimposed by the second transfer color. It is described as "MY" which is a color close to. When the printing paper color is yellow (Y), the first transfer color is described as "WCKM" other than the second transfer color "Y", and the second transfer color is a color close to the printing paper color. Is described as "Y". Similarly, when the printing paper color is green (G), cyan (C), blue (B) or magenta (M), the color that should be the first transfer color (other than the second transfer color) and 2 The color that should be the transfer color for the second time (a color close to the color of the printing paper) is described.

In the dark black (K) column 142, the number of transfers is two, the first transfer color is "WCMY", and the second transfer color is "K". That is, in the black (K) column 142, the number of transfers is set to 2 as in the dark / middle color (Dark / Middle) column 141, the first transfer color is set to a color other than the second transfer color, and the second transfer color is printed. Described as a color close to the paper color. The black (K) column 142 may be included in the dark / middle color column 141.

On the other hand, in the light color (Light) column 143, the printing paper color is any of red (R), yellow (Y), green (G), cyan (C), blue (B), and magenta (M). Also in the case of, the number of transfer times is set to 1, and the transfer color is described as all the colors of "WCMYK".
Further, in the light color white (W) column 144, the number of transfers is one as in the case of the light color (Light) column 143, and the transfer color is described as all the colors of "WCMYK". The white (W) column 144 may be included in the light color (Light) column 143.

Next, the operation of determining the number of transfers and the transfer color in step S23 shown in FIG. 5 will be described. FIG. 10 is a flowchart for determining the number of transfers and the transfer color according to the first embodiment.
Step S31: First, the control unit 50 of the image forming apparatus 1 determines whether or not the white toner usage range information Rwt input from the print data receiving unit 61 is “not used”. When the control unit 50 of the image forming apparatus 1 determines that the white toner usage range information Rwt is “not used”, the process proceeds to step S32. On the other hand, when the control unit 50 of the image forming apparatus 1 determines that the white toner use range information Rwt is not the case of "not using", the process proceeds to step S33.

Step S32: The control unit 50 of the image forming apparatus 1 refers to the transfer number transfer color determination table 68, and sets the transfer number regardless of the color of the printing paper color information Cp according to the description in the “not used” column 131. The transfer color is set to "CMYK" once, and this process is completed. That is, the control unit 50 of the image forming apparatus 1 returns to step S23 shown in FIG. 5, and prints on the printing paper P by the operation after step S24 based on the determined transfer count and transfer color.

Step S33: On the other hand, when the control unit 50 of the image forming apparatus 1 determines that the white toner usage range information Rwt input from the print data receiving unit 61 is not “not used”, the print paper color information Cp is changed. It is determined whether or not it is "light". In this determination, whether or not any button in the selection button sequence 114 shown in FIG. 7 may be pressed may be determined by a button number or the like.
When the control unit 50 of the image forming apparatus 1 determines that the printing paper color information Cp is “light”, the control unit 50 proceeds to step S34 for determining the transfer color in the one-time fixing mode.
Further, the control unit 50 of the image forming apparatus 1 determines that the printing paper color information Cp is not "light" but dark "dark / middle" or "black". At that time, the process proceeds to step S35 for determining the transfer color in the fixing mode twice.

Step S34: The control unit 50 of the image forming apparatus 1 refers to the transfer number transfer color determination table 68 shown in FIG. 9, and according to the light color column 143, regardless of the color of the printing paper color information Cp. The number of transfers is one, and the transfer color is "WCMYK".
Step S35: When the printing paper color information Cp is not "light", that is, when the printing paper color information Cp is not "light", that is, when the printing paper color information Cp is "dark / middle" or "black" of the dark color system. Determines whether or not the white toner usage range information Rwt is "the entire printing paper".

When the control unit 50 of the image forming apparatus 1 determines that the white toner usage range information Rwt is “the entire printing paper”, the process proceeds to step S36. On the other hand, when the control unit 50 of the image forming apparatus 1 determines that the white toner usage range information Rwt is “only the image portion”, the process proceeds to step S37.
Step S36: When the control unit 50 of the image forming apparatus 1 determines that the white toner usage range information Rwt is “the entire printing paper”, the control unit 50 refers to the transfer count transfer color determination table 68 shown in FIG. 9 and “prints”. The number of transfers is set to 2 according to the description in the "whole paper" column 132. Further, the control unit 50 of the image forming apparatus 1 sets the first transfer color as "W" and the second transfer color as "CMYK".

Step S37: On the other hand, when the control unit 50 of the image forming apparatus 1 determines that the white toner usage range information Rwt is “only the image portion”, the dark color / intermediate color (Dark / Middle) column 141 or the dark color (Dark / Middle) column 141 shown in FIG. 9 or According to the black (K) column 142, the number of transfers is set to 2. Further, the control unit 50 of the image forming apparatus 1 sets the first transfer color to a color other than the second transfer color, and sets the second transfer color to a color close to the printing paper color.

For example, when the printing paper color information Cp is "black", the control unit 50 of the image forming apparatus 1 sets the number of transfers to two. Further, the control unit 50 of the image forming apparatus 1 sets the first transfer color to "WCMY" other than the second transfer color black (K), and sets the second transfer color to "black (K)" which is close to the printing paper color. ) ”.
In this way, the control unit 50 of the image forming apparatus 1 determines the transfer count and the transfer color based on the printing paper color information Cp and the white toner usage range information Rwt by the transfer count transfer color determination unit 63. After that, the control unit 50 of the image forming apparatus 1 returns to step S23 shown in FIG. 5, and prints on the printing paper P by the operation after step S24 based on the determined transfer count and transfer color.

(Printing operation)
Next, the printing operation executed by the image forming apparatus 1 according to the first embodiment in step S27 shown in FIG. 5 will be described. This printing operation will be described with reference to FIGS. 1 to 4.
The image forming apparatus 1 shown in FIG. 1 receives WCMYK binarized image data from the halftone processing unit 66 by the printing unit 67 (see FIG. 4), and transfers the number of transfers and the transfer color from the transfer number transfer color determination unit 63. Is received, the printing operation is started as follows.

First, the print control unit 52 (see FIG. 3) drives the paper feed roller 15 and the paper feed transfer roller pairs 16 and 17 of the paper feed unit 7 shown in FIG. 1 by the motor drive unit 54 (see FIG. 3). The printing paper P is fed from the paper feed tray 6. Further, the print control unit 52 adjusts the print timing by the timing detection sensor 20 and conveys the printing paper P to the transfer unit 10. At this time, the print control unit 52 confirms that the transport state of the print paper P is normal by the paper feed detection sensor 19.

On the other hand, the print control unit 52 transmits the driving force of the motor driving unit 54 to the rotation axis of the photoconductor drum 30 of the image forming unit 18 by a connecting gear or the like (not shown) in the direction shown by the arrow V in FIG. 2A. The photoconductor drum 30 is rotated. Similarly, the print control unit 52 transmits the drive of the motor drive unit 54 to the rotation axis of the supply roller 35, and rotates the supply roller 35 in the direction indicated by the arrow T in FIG. 2A. The toner Tn is supplied from the supply roller 35 to the developing roller 34 by the rotation of the supply roller 35. The thickness of the toner Tn supplied to the developing roller 34 is regulated by the developing blade 36, and a toner Tn having a constant thickness is formed on the developing roller 34. At this time, the developing roller 34 and the charging roller 32 rotate along with the rotation of the photoconductor drum 30 and rotate in the directions indicated by the arrows U and W in FIG. 2A.

Further, the print control unit 52 applies a predetermined charging voltage to the charging roller 32 by the power supply unit 55 (see FIG. 3) to uniformly charge the surface of the photoconductor drum 30. After that, the print control unit 52 causes the LED head 31 to emit light, and forms an electrostatic latent image pattern based on the print data on the surface of the photoconductor drum 30.
Further, the print control unit 52 applies a predetermined supply voltage to the supply roller 35 and applies a predetermined development voltage to the developing roller 34 by the power supply unit 55. The toner Tn on the developing roller 34 is charged to a predetermined amount by the supply voltage and the developing voltage. After that, the toner Tn on the developing roller 34 adheres to the electrostatic latent image pattern formed on the photoconductor drum 30, and forms a toner image on the photoconductor drum 30.

On the other hand, the print control unit 52 drives the belt drive roller 22 (see FIG. 1) by the motor drive unit 54 and simultaneously drives the driven rollers 23 to 25, and moves the intermediate transfer belt 38 in the direction indicated by the arrow E in FIG. 1 (paper surface). Rotate clockwise). Due to this rotation, the toner image formed on the photoconductor drum 30 is primarily transferred to the intermediate transfer belt 38 by the primary transfer roller 37 rotating in the direction indicated by the arrow Y in FIG. 2 (a).
As described above, the toner images formed on the photoconductor drum 30 of the image forming unit 18 of each color of WCMYK are sequentially superimposed on the intermediate transfer belt 38 and primary transferred, and the primary transfer image Ts shown in FIG. 2A is obtained. It is formed.

Further, the print control unit 52 moves the intermediate transfer belt 38 to the transfer unit 10 in the direction indicated by the arrow E in FIG. 2B, and moves the primary transfer image Ts on the intermediate transfer belt 38 in the direction indicated by the arrow D. Secondary transfer is performed on the transferred printing paper P to form a transfer image Tz. At this time, the print control unit 52 controls the secondary transfer by applying a predetermined transfer voltage to the transfer roller 26 by the power supply unit 55. After that, the print control unit 52 conveys the printing paper P on which the transfer image Tz is transferred to the fixing device 11 by the motor driving unit 54, and fixes the transfer image Tz on the printing paper P. That is, the print control unit 52 heats the heating roller 11b of the fixing device 11 by the power supply unit 55, presses the printing paper P on which the transfer image Tz is formed by the pressurizing roller 11a, and prints the transfer image Tz on the printing paper P. To settle in.

After that, the print control unit 52 conveys the printing paper P by the discharge transfer roller pairs 75 to 77 shown in FIG. 1 and discharges the printing paper P to the discharge stacker 13 in the one-time fixing mode in which the number of transfers is “1 time”. .. At this time, the print control unit 52 confirms that the state of transporting the printing paper P to the discharge stacker 13 is normal by the discharge detection sensor 21.
On the other hand, in the double fixing mode in which the number of transfers is "2 times", the print control unit 52 does not eject the printing paper P on which the first transfer image Tz is transferred and fixed, and the return transfer mechanism 28 Transport to. That is, the print control unit 52 switches the transport path by a transport path switching guide (not shown), transports the printing paper P in the direction indicated by the arrow H in FIG. 1 by the return transport roller pair 27, and further, the return transport roller pair 71 and According to 72, the paper is conveyed in the directions shown by arrows J and L in FIG.

The print control unit 52 primary-transfers the primary transfer image Ts of the remaining colors to the intermediate transfer belt 38 while adjusting the printing timing by the timing detection sensor 20 in the same manner as the first time. That is, the print control unit 52 forms a toner image by the image forming unit 18 of the remaining colors, transfers the toner image to the intermediate transfer belt 38, and forms the primary transfer image Ts. After that, the print control unit 52 displays the primary transfer image of the remaining colors on the transfer image Tz on the printing paper P, which is first fixed by the transfer unit 10 and conveyed in the direction indicated by the arrow D in FIG. Ts is superimposed and secondary transfer is performed. Further, the print control unit 52 fixes the transfer image Tz of the remaining colors by the fixing device 11, and discharges the printing paper P to the discharge stacker 13 by the discharge unit 12. When performing double-sided printing, the front-back reversing mechanism 29 is used to similarly print on both sides of the printing paper P.
In this way, the printing unit 67 (see FIG. 4) controls printing by the printing control unit 52 and prints on the printing paper P.

(Explanation of transfer image)
Next, the transfer image Tz formed by the image forming apparatus 1 according to the first embodiment will be described. FIG. 11 is an explanatory diagram of a transfer image formed by the image forming apparatus according to the first embodiment. FIG. 11 is a transfer image Tz when the white toner usage range information Rwt is “only the image portion”, and is a view of the printing paper P viewed from the side surface direction with respect to the transport direction. In FIG. 11A, W layer 81, C layer 82, M layer 83 and Y layer 84 (hereinafter referred to as “W layer 81 and the like”) are formed on the black printing paper P by the first transfer. It is a schematic diagram of the transfer image Tz in which the K layer 85 was formed by the second transfer. FIG. 11B shows a transfer image Tz in which the W layer 81 or the like is formed on the black printing paper P by the first transfer, and the image area of the K layer 85 is enlarged by the image area enlargement portion 65 in the second transfer. It is a schematic diagram of.

As shown in FIG. 11, when the printing paper color information Cp is black, the image forming apparatus 1 forms the W layer 81 with white toner as a base in the first transfer in order to improve the color reproducibility. The image forming apparatus 1 is formed by superimposing the C layer 82, the M layer 83, and the Y layer 84 of cyan (C), magenta (M), and yellow (Y) toners Tn on the image forming apparatus 1 in this order. After that, the image forming apparatus 1 is formed by further superimposing the black (K) K layer 85 in the second transfer.

In this way, when the transfer is performed in two steps, as shown in FIG. 11A, the K layer 85 moves from the position of the W layer 81 or the like as a desired position in the direction indicated by, for example, the arrow Z. It shifts. This misalignment occurs due to a detection error of the timing detection sensor 20 shown in FIG. 1 between the first transfer and the second transfer, a variation in the skew amount of the printing paper P, and the like. As a result, a misalignment occurs between the W layer 81 and the like due to the first transfer and the K layer 85 due to the second transfer, and a gap is formed between the eaves (overhang) region 88 that covers the W layer 81 and the like. Crevasse region 89 occurs as a streak. The misalignment can occur in any of the front, rear, left, and right directions with respect to the transport direction of the printing paper P, and the direction of occurrence differs depending on the cause of occurrence.

In the image forming apparatus 1 according to the first embodiment, the transfer number transfer color determination unit 63 sets the second transfer color to a color close to black of the printing paper color, that is, black (K), and forms the K layer 85. Therefore, even if such a misalignment occurs, the streaks and the like generated by the eaves region 88 are not conspicuous when viewed from the upper surface of the printing paper P.

Further, in the image forming apparatus 1 according to the first embodiment, the image region of the K layer 85 is defined by the image region enlargement unit 65 as shown by the left and right shaded portions of the K layer 85 shown in FIG. 11 (b). Expand by length ΔLα. As a result, in the K layer 85, a first enlarged region 91 having a length ΔLα of black (K) is added to the gap region 89. Therefore, the image forming apparatus 1 can make the streaks and the like generated by the gap region 89 inconspicuous. The predetermined length ΔLα to be expanded may be obtained by measuring the length of the misalignment by an experiment or the like, and may be, for example, about 0.2 mm to 0.3 mm.
In this case, in the K layer 85 shown in FIG. 11B, a second enlarged region 92 having a length ΔLα is also added to the eaves region 88 at the same time, but the second enlarged region 92 is also black in the printing paper color. The second enlarged region 92 is also inconspicuous because it is formed by black (K) having a color close to.

Further, the transfer image Tz formed by the image forming apparatus 1 according to the first embodiment will be described with reference to the top view. FIG. 12 is a top view of a transfer image formed by the image forming apparatus according to the first embodiment. FIG. 12 is a transfer image Tz when the white toner usage range information Rwt is “only the image portion”, as in FIG. FIG. 12 shows that the black printing paper P has a circular base of the W layer 81, the uppermost layer has the K layer 85 of the black ring-shaped figure, and the outer diameter of the ring figure of the K layer 85 is It is shown that it is slightly shorter than the circular diameter of the W layer 81. Further, between the W layer 81 of the base and the K layer 85 of the uppermost layer, the circular CMY layers 82 to 84 having the same diameter as the outer diameter of the annular figure are printed in light gray, and therefore, as a top view, Is a schematic diagram of the transfer image Tz in which the CMY layers 82 to 84 appear in the inner diameter of the annular figure.

FIG. 12A shows an ideal transfer image Tz formed by the two-time fixing mode and with no deviation in the second K layer 85. FIG. 12B is a transfer image Tz formed by the second fixing mode and in which the K layer 85 is displaced for the second time. In the figure, the gap region 89 is exaggerated. FIG. 12C is a transfer image Tz in which the image region of the K layer 85 is formed for the second time by the image region enlargement portion 65 according to the present embodiment, and the portion X surrounded by the broken line is the first enlarged region. It is an enlarged view around 91 and the second enlarged area 92. In the figure, the first enlarged region 91 and the second enlarged region 92 are exaggerated.

In the double fixing mode, as shown in FIG. 12B, the second K layer 85 is displaced with respect to the first W layer or the like, for example, in the direction of arrow Z, so that a positional deviation occurs. As a result, a gap region 89 is generated, and streaks and the like are generated on the opposite side of the circular figure of the K layer 85 in the arrow Z direction. On the other hand, in the arrow Z direction of the circular figure of the K layer 85, the eaves region 88 is generated so as to cover the W layer 81 and the like in the K layer 85, but it is not conspicuous because the printing paper P is black.
The image forming apparatus 1 according to the first embodiment enlarges the image area of the K layer 85 by a predetermined length ΔLα by the image area enlargement unit 65, as shown in FIG. 12 (c). Therefore, the gap region 89 generated on the opposite side of the annular figure of the K layer 85 in the arrow Z direction disappears due to the first enlarged region 91, and the streaks and the like become inconspicuous.

On the other hand, in the direction of the arrow Z of the circular figure of the K layer 85, the image region of the K layer 85 is inconspicuous because the printing paper P is black, although the eaves region 88 is expanded by adding the second enlarged region 92.
In addition, the enlargement of the image region of the K layer 85 is a second enlargement of the length ΔLα in the outer region R2 of the image region of the K layer 85, as shown by the portion X surrounded by the broken line in FIG. 12 (c). The region 92 is added, and the first enlarged region 91 is also added to the inner region R1 of the image region of the K layer 85. Therefore, even when streaks or the like occur due to misalignment in the inner region R1 of the image region of the K layer 85, the streaks or the like can be made inconspicuous by the second enlarged region 92.
In the above description, the direction of the misalignment of the K layer 85 is described as the arrow Z direction, but the direction of the misalignment is the direction opposite to the arrow Z direction side or the left and right in the arrow Z direction as the paper surface vertical direction. Even when the direction is shifted, the streaks and the like generated due to the misalignment can be made inconspicuous.

As described above, according to the image forming apparatus 1 according to the first embodiment, since the second transfer color is a color close to the printing paper color, it is generated due to the misalignment of the first and second transfer images Tz. The eaves area 88 to be printed can be made inconspicuous. Further, according to the image forming apparatus 1 according to the first embodiment, the image region of the second transfer color is expanded in all directions by a predetermined length ΔLα, so that the first and second times are performed. The gap region 89 generated by the misalignment of the transferred image Tz can also be made inconspicuous.

(Modification example 1)
The present invention is not limited to the above embodiments, and can be modified based on the gist of the present invention, and they are not excluded from the scope of the present invention. For example, in the above description of the embodiment, the printer is described as an example of the image forming apparatus 1, but the image forming apparatus 1 may be a copying machine, a facsimile, and a multifunction device. Further, in the above description of the embodiment, the electrophotographic image forming apparatus 1 has been described as an example, but the printing method may be an electrostatic recording method, an electrostatic printing method, a toner jet method, or the like. Further, in the above description of the embodiment, the printing method has been described as an intermediate transfer method, but the printing method may be a direct transfer method.

(Modification 2)
Further, in the above description of the embodiment, the toner is described as an example as the developing agent, but the developing agent may be a developing agent such as other inks. Further, in the above description of the embodiment, the printing paper P has been described as an example as the printing medium, but the printing medium may be a card-shaped printing medium or a booklet-shaped printing medium. .. Further, in the above description of the embodiment, the spot color developer for improving the color reproducibility has been described as the white toner, but the spot color developer may be another toner.

(Modification example 3)
Further, in the description of the above-described embodiment, the image forming apparatus 1 has described an example in which printing is performed by the five-color image forming unit 18 in which the W color is added to the CMYK color, but the following may be used. That is, the image forming apparatus 1 may be configured by an image forming unit 18 having a color different from the WCMYK color, or may be configured by an image forming unit 18 having 6 or more colors.

(Modification example 4)
Further, in the above description of the embodiment, the example of the image forming apparatus 1 which is transferred and fixed in two times is described, but the image forming apparatus 1 is transferred and fixed in a plurality of times of three or more times. The present invention can also be applied in some cases. In this case, the second transfer color in the above description of the embodiment is the transfer color to be transferred and fixed at the end of the plurality of transfers, and the last transfer color is a color close to the printing paper color. The image area of the last transferred color is enlarged by a predetermined length ΔLα.

(Modification 5)
Further, in the above description of the embodiment, the printing paper color is set by the user on the general-purpose terminal 3, but the following may be used. That is, the image forming apparatus 1 may dispose an optical sensor or the like in the vicinity of the transport path for transporting the printing paper P, optically detect the printing paper color, and set the printing paper color as the printing paper color. In this case, the printing paper color setting unit 48 as the printing paper color setting means provided in the printer driver 47 of the general-purpose terminal 3 shown in FIG. 4 may not be provided.

(Modification 6)
Further, in the above description of the embodiment, it has been described that the user sets the printing paper color and the white toner usage range in the general-purpose terminal 3, but the user can make these settings in the image forming apparatus 1. You may do it. In this case, the image forming apparatus 1 is provided with the printing paper color setting unit 48 and the white toner use range setting unit 49, and the user can set the printing paper color and use the white toner using the operation display unit 14 of the image forming apparatus 1. To enable the setting of.

(Modification 7)
Further, in the above description of the embodiment, the image forming apparatus 1 has been described so as to enlarge the image area of the second transfer color by a predetermined length by the image area enlargement unit 65. You may do so. That is, the printer driver 47 of the image forming apparatus 1 or the general-purpose terminal 3 displays a setting screen on which the enlargement length can be arbitrarily set on the operation display unit 14 or the display device 41, and arbitrarily sets the enlargement length ΔLα by the user. It may be possible to set it.

1 Image forming device 2 Image forming system 3 General-purpose terminal 4 Network 8 Image forming unit 9 Transfer unit 10 Transfer unit 11 Fixer 18 Image forming unit 37 Primary transfer roller 38 Intermediate transfer belt 40 Terminal control unit 46 Application 47 Printer driver 48 Printing paper Color setting unit 49 White toner usage range setting unit 50 Control unit 52 Print control unit 61 Print data reception unit 63 Transfer count transfer color determination unit 64 White amount adjustment processing unit 65 Image area enlargement unit 67 Printing unit 68 Transfer count transfer color determination table P printing paper Tz transfer image Cp printing paper color information Rwt white toner usage range information

Claims (15)

An image forming apparatus for printing by transferring and fixing a developer of a plurality of colors on a printing medium according to the number of transfers once or the number of transfers divided into a plurality of times based on print data.
A print data receiving means for receiving the print data including the print medium color information for specifying the color of the print medium, and
A transfer number transfer color determining means for determining the transfer count and the color of the developer to be used based on the print medium color information of the print data received by the print data receiving means is provided.
When the color of the print medium in the print medium color information is a dark color system, the transfer number transfer color determination means sets the transfer number to the plurality of times, and sets the color of the developer of the transfer in the last time to the transfer number. An image forming apparatus for determining a color of print medium color information close to the color of the print medium. The print data further includes information on the range of use of the spot color developer that specifies the range on the print medium in which the spot color developer is used.
The transfer number transfer color determining means determines the transfer number and the color of the developer to be used based on the print medium color information and the special color developer use range information, and the special color developer use range information is the special color. When the developer is used only in the portion where the image is formed and the color of the print medium is the dark color system, the number of transfers is set to the plurality of times, and the development of the last transfer is performed. The image forming apparatus according to claim 1, wherein the color of the agent is determined to be a color close to the color of the print medium in the print medium color information. The image forming apparatus according to claim 2, further comprising an image area expanding means for expanding an image area of the color of the developing agent in the printing medium in the last round of the transfer by a predetermined length. The image forming apparatus according to claim 2, wherein the special color developer is white toner. The claim is characterized by comprising a storage unit for storing a transfer number transfer color determination table to be referred to when determining the transfer number and the color of the developer from the spot color developer use range information and the print medium color information. 4. The image forming apparatus according to 4. A print control for transmitting the print data for printing by transferring and fixing the developer of a plurality of colors on a printing medium according to the number of transfers once or the number of transfers divided into a plurality of times based on the print data to an image forming apparatus. It ’s a device,
A print medium color setting means for setting print medium color information for specifying the color of the print medium, and
It is provided with a special color developer use range setting means for setting the special color developer use range information for specifying the range on the print medium in which the special color developer is used.
In order for the image forming apparatus to determine the number of transfers and the color of the developer based on the print medium color information and the spot color developer use range information, the print medium color information and the spot color developer use range information are obtained. A print control device characterized by generating the added print data. The print control device according to claim 6, further comprising an operation display unit for displaying the color of the print medium in the print medium color information so as to be selectable in either a dark color system or a light color system. Further, the operation display unit uses the spot color developer for the entire print medium or uses the spot color developer for a portion where an image of the print medium is formed as the spot color developer use range information. The print control device according to claim 7, wherein any one of the above-mentioned special color developer and the special color developer is not used or is displayed in a selectable manner. A printing process in which a developer of a plurality of colors is transferred and fixed on a printing medium according to the number of transfers once or the number of transfers divided into a plurality of times based on the print data, and printing.
A print data receiving step of receiving the print data including the print medium color information for specifying the color of the print medium and the spot color developer use range information for specifying the range on the print medium using the spot color developer.
An image forming method comprising the transfer number transfer number transfer color determination step of determining the transfer count and the color of the developer based on the print medium color information and the spot color developer use range information. In the transfer count transfer color determination step, when the special color developer usage range information is used only for a portion where an image is formed and the print medium color information is a dark color system, the special color developer is used only in a portion where an image is formed. The image formation according to claim 9, wherein the number of transfers is set to a plurality of times, and the color of the developer in the last transfer is a color close to the color of the print medium in the print medium color information. Method. The image forming method according to claim 10, further comprising an image area enlargement step of expanding an image area in the print medium of the color of the developer in the last inning of the transfer by a predetermined length. Printing data transmission for transmitting print data for printing by transferring and fixing a developer of a plurality of colors on a printing medium according to the number of transfers once or the number of transfers divided into a plurality of times based on the print data. Process and
A print medium color setting process that accepts the setting of print medium color information that specifies the color of the print medium, and
A special color developer usage range setting process that accepts the setting of special color developer usage range information that specifies a range on the print medium that uses the special color developer, and a special color developer usage range setting process.
In order for the image forming apparatus to determine the number of transfers and the color of the developer based on the print medium color information and the spot color developer use range information, the print medium color information and the spot color developer use range information are obtained. A print control method including a print data generation step of generating added print data. The print medium color setting step is
The print control method according to claim 12, wherein the print medium color information is divided into a dark color system and a light color system, and the setting is accepted. In the step of setting the range of use of the special color developer, whether the special color developer is used for the entire printing medium, the special color developer is used for a portion where an image is formed, or the special color developer is not used. 12. The print control method according to claim 12, wherein any of the above settings is accepted. An image forming apparatus for transferring and fixing a developer of a plurality of colors on a printing medium according to the number of transfers once or the number of transfers divided into a plurality of times based on the print data, and the print data on the image forming apparatus. An image forming system consisting of a print control device for transmission.
The image forming apparatus
A print data receiving means for receiving the print data including the print medium color information for specifying the color of the print medium and the spot color developer use range information for specifying the range on the print medium using the spot color developer. ,
The transfer number transfer color determining means for determining the transfer count and the color of the developer to be used based on the print medium color information and the spot color developer use range information of the print data received by the print data receiving means. Prepare,
The print control device is
A print medium color setting means for setting the print medium color information, and
The special color developer use range setting means for setting the special color developer use range information is provided.
In order for the image forming apparatus to determine the number of transfers and the color of the developer based on the print medium color information and the spot color developer use range information, the print medium color information and the spot color developer use range information are obtained. By generating the added print data,
An image forming system characterized in that printing is performed by the image forming apparatus based on the print data.

Images