JP2016045272A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that can avoid an increase in size and complexity of the apparatus occurring when a clear toner is used, and create an appropriate gloss mark irrespective of a toner image in a background part.SOLUTION: In an image forming apparatus capable of 2-pass image formation, an image created in a second image forming and fixing step can be visually recognized and cannot be read by a scanner.SELECTED DRAWING: Figure 14

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus and method for forming an image using an electrophotographic process, and more particularly to an image forming apparatus capable of controlling gloss and capable of gloss modulation suitable for, for example, a laser beam printer and a copying machine. Regarding the method.

  In recent gloss control, not only uniform gloss control over the entire surface, but also an image forming apparatus capable of intentionally forming different gloss areas on one output image by using different marks such as security marks. Yes. As an output image as security or original guarantee, even if it is easy for a human to recognize a content portion, it is impossible in a copier scanner.

  For example, by printing an image using transparent toner or ink as one method, a difference between reflected light and scattered light is created, and if a person holds the paper at a certain angle, it can be recognized as a gloss difference, but the output This is to prevent detection by a copier scanner that can read only at an angle perpendicular to an object.

  In order to express the partial gloss mark using the transparent toner as described above, several methods have been proposed. In the case of a method in which a color toner image on a recording material is temporarily fixed and a clear toner image is formed on the recording material as in Patent Document 1 and Patent Document 2, and then the second fixing is performed, The partial gloss mark as described above can be created by setting the toner region as a region where gloss is desired to be controlled. Further, in Patent Document 3, it is raised that the expression is realized by performing different halftone processes in two areas where different glosses are to be expressed.

JP 2002-318482 A JP 2006-251722 A JP 2010-143219 A

  However, when a clear toner is used as a method for forming a gloss mark on one output image, it is necessary to prepare a clear toner in addition to a colored toner, which requires a significant increase in manufacturing costs. Become. Furthermore, at least a storage container for clear toner, a clear toner replenishing unit, and a developing device are required, and an image forming unit for clear toner is also required in a tandem type image forming apparatus. Furthermore, when the image forming conditions are different, an image forming program for clear toner is required, resulting in a significant increase in cost and an increase in the size of the apparatus.

  In addition, when image processing such as halftone screen processing that differs only in the gloss mark portion is performed, the effect cannot be exhibited in a so-called solid image in which image processing such as screen processing is not performed.

In order to solve the above-mentioned problem, the invention described in claim 1
An image processing device that performs predetermined image processing on an input image from an external device, and a uniformly charged image carrier surface is exposed based on the image data processed by the image processing device to form a latent image. An exposing unit to be formed, a developing unit that visualizes the latent image with a charge-holding toner by applying a predetermined developing bias, and the toner image to the recording medium directly or via an intermediate transfer member. An image forming step of forming an output image of an unfixed toner image on the recording medium by an image forming means comprising a transfer means for transferring;
Fixing the toner image transferred onto the recording medium, and forming an output image of the fixed toner image, and
On the first output image output by the first image output step that performs the fixing step after the image forming step, the final output image is again obtained by the second image output step that performs the image forming step and the fixing step. In an image forming apparatus provided with a multiple image forming and fixing step,
The gloss of the final output image is designated by the user from the operation unit or the control screen, and has a gloss area designation means capable of partially changing the gloss of the image area of the designated area, When it is designated by the glossiness area designation means so as to partially change the gloss of the image area of the designated area, after the first image formation and fixing other than the designated area and area, An image forming apparatus that forms a second image and fixes the designated area to form an image.

  According to a second aspect of the present invention, when the glossiness area designating unit designates the glossiness of the image portion of the designated area to be partially changed, the designated area and the other area are designated. The image forming apparatus according to claim 1, wherein the difference between the image forming apparatus and the image forming apparatus can be visually confirmed and cannot be read by a scanner.

  According to a third aspect of the present invention, the fixing conditions in the first fixing step and the fixing conditions in the second fixing step are made different. It is.

  According to a fourth aspect of the present invention, the amount of heat given to the toner image in the first fixing step is larger than the amount of heat given to the toner image in the second fixing step. The image forming apparatus according to any one of the above.

  According to the present invention, in an image forming apparatus that forms an image through two fixing steps, it is easy for a human to recognize a content portion in an area designated by a user without using transparent toner. In addition, it is possible to form a mark portion that is impossible in a copying machine scanner.

Explanatory drawing of the image forming part in the embodiment 1 is a block diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment. The block diagram which shows the hardware constitutions of the external input device shown in FIG. The figure which shows the screen displayed on the display of the image forming apparatus in an Example The flowchart which shows an example of the control processing procedure in an Example Schematic diagram showing an example of a print screen of an application displayed on the display device of the external input device when a print instruction is given Schematic diagram showing an example of a user interface of a printer driver displayed on a display device of an external input device in order to perform print settings Schematic diagram showing an example of a setting screen displayed when the original guarantee button is selected in the user interface of the printer driver shown in FIG. Schematic diagram showing an example of the setting screen displayed when the position designation of the original guarantee mark is selected on the setting screen shown in FIG. Schematic diagram showing an example of the setting screen displayed when the foreground shape of the original guarantee mark is selected on the setting screen shown in FIG. The schematic diagram which shows an example of the screen which performs the character input displayed when the character button is selected in the said part shape setting shown in FIG. The schematic diagram which shows an example of the setting screen displayed when the background part shape of an original guarantee mark is selected on the setting screen shown in FIG. An example of a document containing the original warranty mark Schematic diagram showing how a human eye can sense a noticeable difference in the glossy finish of a page, but not possible with a scanner detector Relationship between image DUTY and reflection density when using low gloss paper Relationship between image DUTY and gloss when low gloss paper is used When the background is an image DUTY 100% due to the relationship between the image DUTY and reflection density when 2PASS image formation is performed using low gloss paper When the background is the image DUTY 100% due to the relationship between the image DUTY and the glossiness when 2PASS image formation is performed using low gloss paper When the background is an image DUTY 100% due to the relationship between the image DUTY and reflection density when 2PASS image formation is performed using low gloss paper When the background is the image DUTY 100% due to the relationship between the image DUTY and the glossiness when 2PASS image formation is performed using low gloss paper Relationship between image DUTY and reflection density when using high gloss paper Relationship between image DUTY and gloss when high gloss paper is used When the background is 100% due to the relationship between the image DUTY and reflection density when 2PASS image formation is performed using high gloss paper When the background is the DUTY 100% due to the relationship between the image DUTY and the glossiness when the 2PASS image is formed using high gloss paper When the background is 100% due to the relationship between the image DUTY and reflection density when 2PASS image formation is performed using high gloss paper When the background is the DUTY 100% due to the relationship between the image DUTY and the glossiness when the 2PASS image is formed using high gloss paper When the background portion is 80% due to the relationship between the image DUTY and reflection density when 2PASS image formation is performed using low gloss paper When the background is the DUTY 80% due to the relationship between the image DUTY and the glossiness when the 2PASS image is formed using low gloss paper When the background portion is 80% due to the relationship between the image DUTY and reflection density when 2PASS image formation is performed using low gloss paper When the background is the DUTY 80% due to the relationship between the image DUTY and the glossiness when the 2PASS image is formed using low gloss paper When the background is an image DUTY 60% due to the relationship between the image DUTY and reflection density when 2PASS image formation is performed using low gloss paper When the background is an image DUTY 60% due to the relationship between the image DUTY and the glossiness when 2PASS image formation is performed using low gloss paper When the background is an image DUTY 60% due to the relationship between the image DUTY and reflection density when 2PASS image formation is performed using low gloss paper When the background is an image DUTY 60% due to the relationship between the image DUTY and the glossiness when 2PASS image formation is performed using low gloss paper When the background is an image DUTY 80% due to the relationship between the image DUTY and reflection density when 2PASS image formation is performed using high gloss paper When the background is an image DUTY 80% due to the relationship between the image DUTY and glossiness when 2PASS image formation is performed using high gloss paper When the background is an image DUTY 80% due to the relationship between the image DUTY and reflection density when 2PASS image formation is performed using high gloss paper When the background is an image DUTY 80% due to the relationship between the image DUTY and glossiness when 2PASS image formation is performed using high gloss paper When the background is an image DUTY 60% due to the relationship between the image DUTY and reflection density when 2PASS image formation is performed using high gloss paper When the background is an image DUTY 60% due to the relationship between the image DUTY and reflection density when 2PASS image formation is performed using high gloss paper When the background is an image DUTY 60% due to the relationship between the image DUTY and reflection density when 2PASS image formation is performed using high gloss paper When the background is an image DUTY 60% due to the relationship between the image DUTY and glossiness when 2PASS image formation is performed using high gloss paper

  Hereinafter, the present invention will be described more specifically with reference to examples. Although these examples are examples of the best mode of the present invention, the present invention is not limited to these examples.

<Example 1>
(1) Image Forming Unit FIG. 1 shows a schematic cross-sectional configuration of an electrophotographic monochrome image forming apparatus which is an embodiment of the image forming apparatus of the present invention. The monochrome image forming apparatus of the present embodiment is a monochrome electrophotographic apparatus, and is a multifunction machine that functions as a copying machine, a printer, and a facsimile machine. FIG. 2 is a schematic block diagram of the control system.

  First, the image forming unit will be described. Reference numeral 100 denotes an image forming apparatus (hereinafter referred to as an apparatus main body). K is a controller (control circuit unit, control board unit) that performs overall control of the image forming apparatus. Reference numeral 1000 denotes an external input device (external host device) such as a personal computer / facsimile device, which is electrically connected to the controller K via an interface.

  The apparatus main body 100 incorporates an electrophotographic image forming unit in FIG. A and B are a document reading unit (image scanner) and an operation display unit disposed on the upper surface side of the apparatus main body 100. The operation display unit B performs command input from the operator, status notification of the apparatus to the operator, and the like.

  In the document reading section A, 101 is a document table glass, and a document pressing plate that can be opened and closed with respect to the glass 101. In the copy (original copy) mode, the original to be copied is placed on the glass 101 with the image surface facing downward according to a predetermined placement standard, and the presser plate 22 is placed thereon to set the original O. It is also possible to adopt a configuration in which a sheet-like document is automatically fed onto the glass 101 by using a press plate as an automatic document feeder (ADF, RDF).

  Then, after setting a desired copy condition by the operation display unit B, the copy start key 400 (FIG. 3) is pressed. Then, the moving optical system 103 is driven to move along the lower surface of the glass 101, and the downward image surface of the document O on the glass 101 is optically scanned. The original scanning light is imaged and read on a CCD 104 which is a photoelectric conversion element (solid-state imaging element). The read image signal is input to the image processing unit 105. Then, the image processing unit 105 inputs the processed electrical image information to the controller K. The controller K controls the laser scanning mechanism C to output laser light modulated in accordance with the electrical image information to the image forming unit.

  In the printer mode, electrical image information is input to the controller K of the apparatus main body 100 from a personal computer which is the external host apparatus 1000, and the image forming apparatus functions as a printer. In the present embodiment, the details of the output product creation method when the original guarantee mark is given will be described later.

  In the facsimile reception mode, electrical image information is input from the counterpart facsimile apparatus, which is the external host apparatus 1000, to the controller K of the apparatus main body 100, and the image forming apparatus functions as a facsimile receiver.

  In the facsimile transmission mode, the electrical image information of the original photoelectrically read by the original reading unit A is input from the image processing unit 105 to the controller K and transmitted to the counterpart facsimile machine, and the image forming apparatus functions as a facsimile transmitter. To do.

  Here, as a method for outputting an image, a normal one-time fixing output mode in which a monochrome image formed product is output in one fixing step, or an original by partially changing the gloss by performing two fixing steps. There is an original guarantee processing mode for giving a guarantee mark.

  An image forming unit is disposed in the apparatus main body 100 shown in FIG. 1, and is formed through a process of latent image, development, and transfer. The image forming unit includes an electrophotographic photosensitive drum 3 which is an image carrier in this example, and a black toner image is formed on the photosensitive drum 3. An intermediate transfer member 130 is installed adjacent to each photosensitive drum 3, and each color toner image formed on the photosensitive drum 3 is primarily transferred onto the intermediate transfer member 130, and then onto the recording material P at the secondary transfer portion. Transcribed. Further, the recording material P onto which the toner image has been transferred is fixed to the toner image by heating and pressurizing at the fixing unit 9 and then discharged out of the apparatus as a recorded image.

  A drum charger 2, a developing device 1, a primary transfer charger 24, and a cleaner 4 are provided on the outer periphery of the photosensitive drum 3, and a light source device and a polygon mirror (not shown) are further provided above the apparatus.

  The laser beam emitted from the light source device is scanned by rotating the polygon mirror, the light beam of the scanning beam is deflected by the reflection mirror, and is condensed on the bus bar of the photosensitive drum 3 by the fθ lens and exposed. A latent image corresponding to the image signal is formed on the photosensitive drum 3.

  The developing device 1 is filled with a predetermined amount of toner as a developer by a supply device (not shown). Each developing device 1 develops a latent image on the photosensitive drum 3 to form a toner image. As the toner, a toner using a polyester resin was used. The toner can also be produced by a pulverization method, but as a method for producing the toner, a method for producing the toner directly in a medium such as a suspension polymerization method, an interfacial polymerization method or a dispersion polymerization method (polymerization method) Preferably mentioned. The toner components and the production method are not limited to these.

  The intermediate transfer member 130 is driven to rotate in the direction of the arrow at the same peripheral speed as that of the photosensitive drum 3. The toner image formed and carried on the photosensitive drum 3 has an electric field formed by a primary transfer bias applied to the intermediate transfer body 130 in the process of passing through the nip portion between the photosensitive drum 3 and the intermediate transfer body 130. Intermediate transfer is performed on the outer peripheral surface of the intermediate transfer body 130 by the pressure.

  Reference numeral 11 denotes a secondary transfer roller, which corresponds to the intermediate transfer member 130 and is provided in parallel and in contact with the lower surface portion. A desired secondary transfer bias is applied to the secondary transfer roller 11 by a secondary transfer bias source. The toner image transferred onto the intermediate transfer member 130 is transferred to the recording material P from the paper feed cassette 10 through the registration roller 12 and the pre-transfer guide, and the intermediate transfer member 130 and the secondary transfer roller 11 contact each other. The recording material P is fed to the nip at a predetermined timing, and at the same time, a secondary transfer bias is applied from a bias power source. The toner image is transferred from the intermediate transfer body 130 to the recording material P by the secondary transfer bias.

  After the primary transfer is completed, the transfer residual toner is cleaned and removed by the cleaner 4, and the photosensitive drum 3 is continuously prepared for the next latent image formation. The toner and other foreign matters remaining on the intermediate transfer member 130 are wiped off by bringing a cleaning web (nonwoven fabric) 19 into contact with the surface of the intermediate transfer member 130.

  The transfer material P that has received the transfer of the toner image passes through a conveyance unit 51 provided between the secondary transfer unit and the fixing unit, and is then introduced into the fixing unit 9 and fixed by applying heat and pressure. The output image is discharged to a discharge tray 63. In the normal once fixing output mode, the final output image is output by the above operation.

  In the original guarantee processing mode, the transfer material P that has received the transfer of the toner image passes through the conveyance unit 51 provided between the secondary transfer unit and the fixing unit, and is then introduced into the fixing unit 9 to generate heat and heat. After fixing by applying pressure, the toner passes through the second image forming conveyance path and is again introduced into the secondary transfer portion. In this secondary transfer section, the toner image formed on the intermediate transfer member is transferred in the same image forming process as described above, passes through the conveyance path, undergoes the second fixing process, and is output as a final output image. The

(2) External Input Device Next, the hardware configuration of the external input device shown in FIG. 1 will be described with reference to FIG. FIG. 3 is a block diagram showing a hardware configuration of the external input device shown in FIG. In FIG. 3, reference numeral 301 denotes a CPU that comprehensively controls each device and controller connected to the system bus 312. Further, the ROM 303 or the HDD 304 is necessary for realizing a BIOS (Basic Input / Output System), an operating system program (hereinafter referred to as an OS), which is a control program of the CPU 301, and functions to be described later executed by an external input device. Various programs are stored.

  Reference numeral 302 denotes a RAM that functions as a main memory, work area, and the like for the CPU 301. The CPU 301 implements various operations by loading a program necessary for execution of processing from the ROM 303 or the HDD 304 into the RAM 302 and executing the loaded program.

  Reference numeral 305 denotes a network I / F (interface) that is connected to and communicates with an external device via a network (for example, the LAN 104 shown in FIG. 1), and executes communication control processing in the network. For example, communication using TCP / IP is possible.

  Reference numeral 306 denotes a video I / F (interface), which controls display on a display device such as a display device 311 constituted by, for example, a CRT display (CRT) or a liquid crystal display.

  Reference numeral 307 denotes a pointing device, and 308 denotes a keyboard. A user who operates an external input device can input an instruction to the CPU 301 by operating these devices. These function as an input unit.

  Reference numeral 309 denotes a recording medium drive, which reads data recorded on a recording medium such as a CD-ROM according to the control of the CPU 301.

  Reference numeral 310 denotes an external device I / F (interface), which includes, for example, a port such as USB or IEEE1394, and is used to connect a peripheral device to the external input device.

(3) Print Data Creation and Transmission Processing Hereinafter, print data creation / transmission processing performed by the external input device will be described with reference to FIG.

  FIG. 5 is a flowchart illustrating an example of a control processing procedure according to the present invention, and describes print data creation / transmission processing performed by an external input device. In the figure, S101 to S105 indicate steps.

  First, in step S101, the CPU 301 of the external input device instructs to print data generated by an application such as a document editing application program or a spreadsheet application based on an operation instruction from the user pointing device 307 or the keyboard 308. It is determined whether or not it has been received. If it is determined that a print instruction has been received, the CPU 301 of the external input device causes the display device 311 to display a print screen of the application shown in FIG. Hereinafter, the print screen of the application will be described with reference to FIG.

  FIG. 6 is a schematic diagram illustrating an example of a print screen of an application displayed on the display device 311 of the external input device when a print instruction is given.

  In FIG. 6, reference numeral 3001 denotes a “property” button. When this button is designated by the pointing device 307, the CPU 301 of the external input device displays the print setting screen shown in FIG. 7 on the display device 311 and accepts the print setting.

  Reference numeral 3002 denotes an “OK” button. When this button is instructed by the pointing device 307, the CPU 301 of the external input device executes print processing.

  Returning to the flowchart of FIG. Next, in step S102, upon receiving a print setting instruction by the “property” button 3001, the CPU 301 of the external input device displays screen information as shown in FIG. 7 on the display device 311 of the external input device in order to perform print settings. (Printer Driver User Interface) is displayed and print settings are accepted. When a user operating the external input device gives an operation instruction for the pointing device 307 or the keyboard 308, the CPU 301 of the external input device performs print settings based on the instruction. Hereinafter, the user interface of the printer driver displayed on the display device 311 of the external input device for print setting will be described with reference to FIG.

  FIG. 7 is a schematic diagram illustrating an example of a user interface of a printer driver displayed on the display device 311 of the external input device in order to perform print settings. In FIG. 7, the user performs various settings for the output by instructing the “page setting”, “finishing”, “paper feeding”, “print quality”, and “original guarantee” buttons with the pointing device 307. be able to.

  “Page setting” can specify the document size, the size of the output, the number of copies, the layout, and the like. “Finishing” can designate a printing method such as double-sided printing, a binding margin position, a paper discharge method, and the like. “Paper feeding” can set a paper feeding position in the image forming apparatus, such as a cassette position and a manual feed tray. The “print quality” can change the setting in the image forming apparatus so that the output product is equivalent to the one intended by the user by designating a mode according to the purpose of printing by the user. When the “original guarantee” button in FIG. 7 is instructed by the pointing device 307, a screen for setting the original guarantee shown in FIG. 8 is displayed.

  Reference numeral 1001 denotes a button for designating the position of the original guarantee mark. When the button is selected by the pointing device 307, a screen for designating the position as shown in FIG. 9 is displayed. For example, if the lower right is specified, the original guarantee mark is printed on the lower right of the output. Also, if any is designated, the position of the original guarantee mark can be designated at any position in the preview screen 1011 by the pointing device 307.

Reference numeral 1002 denotes a button for designating the foreground of the original guarantee mark. When the button is selected by the pointing device 307, a screen for designating a shape as shown in FIG. 10 is displayed. For example, if ★ is specified, the foreground shape of the original guarantee mark is output as ★. When a character is specified, a character direct input screen as shown in FIG. 11 is displayed, and the character input in 2001 is output as the foreground.

  Reference numeral 1004 denotes a button for designating the foreground size of the original guarantee mark. Reference numeral 1005 denotes a button for designating the background size of the original guarantee mark. Reference numeral 1006 denotes a button for designating the paper type of the output material. For example, high glossy paper or low glossy paper can be designated.

  If the shape, size, etc. are designated in 1002, 1003, 1004, 1005, a preview of the original guarantee mark is displayed in 1012 and the original guarantee mark designated by the user can be confirmed.

  Reference numeral 2403 denotes an “OK” button. When this button is designated by the pointing device 307, the CPU 301 of the external input device determines the print setting and returns the display to the screen of FIG.

  When the print setting is completed in step S102 and there is a final print instruction by an instruction to the “OK” button 3002 shown in FIG. 6, the process proceeds to step S103 in the CPU 301 of the external input device. If there is no need to make print settings, step S102 need not be performed.

  In step S103, the CPU 301 of the external input device acquires user information logged in to the external input device, and advances the process to step S104.

  In step S104, the CPU 301 of the external input device creates print data based on the print settings set in step S102 and the user information acquired in step S103.

  In step S105, the CPU 301 of the external input device transmits the user information acquired in step S103 and the print data created in step S804 to the designated image forming apparatus 101, and the process ends.

(4) Toner Hereinafter, the toner stored in the developing device of the image forming station will be described. In this embodiment, a polyester resin is used as the toner. Examples of the method for producing the toner include a method for producing the toner directly in a medium such as a pulverization method, a suspension polymerization method, an interfacial polymerization method, and a dispersion polymerization method (polymerization method). In this embodiment, the toner manufactured using the suspension polymerization method was used. The toner components and the production method are not limited to these.

  The toner is mainly composed of a polyester resin and a pigment. The glass transition point (Tg) of the toner used in this example is about 55 ° C.

  Of course, the glass transition point (Tg) of the toner is not limited to this. Changing the type and molecular weight of the resin used for the toner changes its melting characteristics. Therefore, the toner image fixed on the sheet under the same fixing conditions can have different gloss depending on the properties of the toner. Therefore, a toner having a high gloss after fixing can be obtained by using a resin having a low glass transition point (Tg) and being easily soluble. In addition, a toner having a low gloss after fixing can be obtained by using a resin having a high glass transition point (Tg) and hardly soluble.

(5) Fixing Unit The fixing unit is composed of the fixing device 9 in FIG. The configuration of the fixing unit will be described below along the flow in which the toner image transferred to the sheet is fixed. The fixing device 9 includes a fixing roller and a pressure roller. The fixing roller and the pressure roller are in pressure contact with each other, and a fixing nip portion is formed therebetween. In this embodiment, both the outer diameters of the fixing roller and the pressure roller are 80 mm. The lengths of the fixing roller and the pressure roller in the rotation axis direction are both 350 mm. The fixing roller is pivotally supported on the outer wall of the fixing device, and the pressure roller is pressed against the fixing roller at 500 N by a spring (not shown).

  The fixing roller is a laminate in which a rubber layer as an elastic layer and a fluororesin layer as a toner release layer are laminated on an aluminum hollow core metal. Further, a halogen heater as a heating source is installed inside the hollow cored bar. The hollow core metal may be another material such as iron. The heating source may be replaced by using, for example, an IH method using electromagnetic induction heating. The fixing roller is connected to a drive motor via a drive gear train, and rotates by rotational power transmitted from the drive motor. Similar to the fixing roller, the pressure roller is a laminated body in which a rubber layer and a fluororesin layer are laminated on a hollow core metal, and a halogen heater is installed inside the hollow core metal. Further, the pressure roller rotates following the fixing roller.

  Near the surfaces of the fixing roller and the pressure roller, a thermistor is mounted as a detecting means for detecting the respective temperatures. Each thermistor can detect the temperature of the fixing roller or the pressure roller. The temperature detection signal output from the thermistor is notified to the controller K. Thereby, the controller K can control the temperature of the fixing roller and the pressure roller.

  In this embodiment, the controller K controls each halogen heater so that the temperature near the surface of the fixing roller is 155 ° C. and the temperature near the surface of the pressure roller is 100 ° C.

  Under such fixing conditions, the sheet on which the toner image is transferred at the secondary transfer portion passes through the fixing nip portion. As a result, the toner image transferred onto the sheet is fixed on the sheet. The sheet on which the toner image is fixed is discharged out of the apparatus through the conveyance path.

  In addition, after the first fixing process, the sheet when 2PASS image formation is performed is not introduced into the reversal path 52c, but is retransmitted to the secondary transfer unit through the conveyance paths 52a and 52b. The sheet on which the second toner image is transferred at the secondary transfer portion passes through the fixing nip portion again. As a result, the toner image transferred onto the sheet is fixed on the sheet. The sheet on which the toner image is fixed is discharged out of the apparatus through the conveyance path. In normal double-sided image formation, after the first fixing step, the paper is introduced into the reverse path 15c and conveyed so that the image is formed on the sheet surface opposite to the surface on which the first image is formed.

  In this embodiment, the sheet is separated from the fixing device 9 while maintaining a high temperature of about 90 to 110 ° C. immediately after finishing passing through the fixing nip portion of the fixing device 9. Of course, it goes without saying that the temperature at which the sheets are separated is affected by the fixing conditions, the basis weight of the sheets, and the like. Further, although the fixing device 9 of the present embodiment has been described as being constituted by a pair of rollers including a fixing roller and a pressure roller, one or both of the fixing side and the pressure side may be constituted by an endless belt. Further, fixing methods other than those shown above may be used.

(6) Original Guarantee Mark Next, the original guarantee mark when the print data including the original guarantee mark is created by the external input device described above, the data is transmitted to the image forming apparatus, and the document as shown in FIG. 13 is created. Will be described.

  FIG. 13 shows data including an original guarantee mark, which includes a document area 131, a foreground portion 132 and a background portion 133 of the original guarantee mark. Here, the document area 131 and the background portion 133 of the original guarantee mark are subjected to the first fixing process after the first image forming process according to the data. The sheet on which the document area 131 and the background portion 133 of the original guarantee mark are fixed is retransmitted to the secondary transfer section through the conveyance paths 52a and 52b.

On the other hand, an image is formed on the foreground portion of the original guarantee mark so as to be synchronized with the second secondary transfer process. The toner image obtained in the second image forming process is transferred to the retransmitted sheet at the timing when the sheet that has undergone the first fixing process is retransmitted to the secondary transfer unit, and is subjected to the second fixing process. Then, it is discharged out of the machine through the conveyance path.

  Here, the visibility of the created original mark will be described. The original guarantee mark needs to be impossible for a copier scanner, even if it is easy for humans to recognize the content part.

  First, FIG. 14 shows a mechanism in which a human eye can recognize a sheet-like gloss difference but cannot be read by a scanner. Each sheet has a low-gloss area 141 and a high-gloss area 142. When the light 140 from the light source L is incident on the image on the sheet, it is divided into light that is regularly reflected on the surface and light that is irregularly reflected. At this time, a portion where the regular reflection is large is a so-called high gloss portion, and a portion where the regular reflection is small is a low gloss portion.

  When the light beam 140 from the light source L is incident on an image with high glossiness and an image with low glossiness, the human eye uses a regular reflection component of the light beam 140, and the image with high glossiness gives a large amount of regular reflection light. A low-light image can detect a small amount of specularly reflected light, and recognize the difference in the light amount as a gloss difference.

  On the other hand, the scanner reads incident light perpendicular to the sheet. In this case, only a scattered component perpendicular to the sheet can be detected in both a high gloss image and a low gloss image. Since the scattering component is very small compared to the regular reflection component, the scanner cannot detect the difference.

  In other words, humans can recognize the difference in gloss by observing the sheet at an angle at which the specularly reflected light is reflected, whereas the optical optical path is fixed by the scanner and scattered. Only light can be detected. This is the reason why the sheet-like gloss difference can be recognized by the human eye but cannot be read by the scanner.

  Further, when verifying how much gloss difference can be recognized by human eyes, it was found that if the difference between the background portion and the foreground portion is 2 ° in terms of gloss difference, it can be determined. In addition, the glossiness shown here is measured using a 60 ° gloss meter (PG-1M manufactured by Nippon Denshoku).

(When using low gloss paper)
(Relationship between image DUTY, density, and glossiness)
FIG. 15 is a graph showing the relationship between the image DUTY (toner amount) fixed on the sheet surface and the reflection density of the sheet surface on which the toner image is fixed. The vertical axis represents the reflection density. The horizontal axis indicates the image DUTY (toner amount) fixed on the sheet. FIG. 16 is a graph showing the relationship between the image DUTY (toner amount) fixed on the sheet surface and the glossiness of the sheet surface on which the toner image is fixed. The vertical axis represents the reflection density. The horizontal axis indicates the image DUTY (toner amount) fixed on the sheet.

Listed below are various conditions that are considered to affect the gloss of the sheet surface after fixing. As the sheet, mat-coated paper (157 g / m ² of Ulite (trademark) manufactured by Nippon Paper Industries) was used. The printer controller 108 controls the image forming apparatus so that the amount of toner to be formed on the sheet is about 0.55 mg / cm ² when a signal having an image density of 100% is input.

  In addition, the controller K controls the image forming apparatus so that the surface temperature of the fixing roller is about 155 ° C., and the process speed at which the sheet passes through the fixing device is 95 mm / s.

  When an image including the original guarantee mark is formed, the process speed in the first image forming and fixing step, the temperature control temperature of the fixing roller, the process speed in the second image forming and fixing step, and the surface of the fixing roller It is possible to change the temperature control temperature. Even though it is easy for humans to recognize the contents of the original guarantee mark, it must be impossible for a copier scanner, so the foreground part and the background can be easily recognized by humans. It is desirable that there is a certain degree of gloss difference in the part. In this embodiment, the surface temperature of the first fixing roller is controlled to be about 155 ° C. and the process speed is 95 mm / s, and the surface temperature of the second fixing roller is 155 ° C. and the process speed is 285 mm / s. It was controlled to become.

  The toner used is a toner having a glass transition point (Tg) of about 55 ° C. using a polyester resin as described above.

  The conditions for creating the original guarantee mark in this embodiment are listed below.

Foreground image DUTY 10%
Process speed 285mm / s
Temperature control temperature 155 ℃
Background part Image DUTY 100%
Process speed 95mm / s
Temperature control temperature 155 ℃
On the other hand, FIGS. 17 and 18 show the first image forming and fixing process (here, the image forming and fixing process of the background portion of the original guarantee mark) in the image forming apparatus having the image characteristics as shown in FIGS. After that, the image DUTY (toner amount) and the toner image fixed on the sheet surface when the second image forming and fixing process (image forming and fixing process of the foreground portion of the original guarantee mark) is further performed thereon are fixed. It is a graph which shows the relationship between the reflection density and glossiness of the sheet | seat surface made. Note that the original guarantee mark used in this embodiment uses an image with an image DUTY (toner amount) of 100% in the background, and FIGS. 17 and 18 show the image DUTY (toner amount) in the first image formation. ) Is the reflection density and glossiness for each image DUTY (toner amount) when the second image formation and fixing is performed after the 100% image is formed and fixed.

  As can be seen from FIGS. 17 and 18, when the foreground part image is fixed on the background part image (image DUTY 100%), the reflection density and the glossiness are changed. 19 and 20 are graphs in which the low image DUTY side of FIGS. 17 and 18 is enlarged.

  As described above, the original guarantee mark needs to be impossible for a copier scanner even if it is easy for a human to recognize the content portion.

  Table 1 shows the results of verifying whether the original guarantee is visible to humans or can be read by the copier scanner for each image DUTY in FIGS. 19 and 20.

Visibility ○: The original guarantee mark can be visually confirmed.

X: The original guarantee mark cannot be visually confirmed.
Scanner ○: The original warranty mark cannot be read by the scanner.

  X: The original guarantee mark can be read by a scanner.

  In image formation using low-gloss paper in this embodiment, the foreground image DUTY is set to 10%, so that the contents of the original guarantee mark can be recognized as shown in Table 1. Also, it cannot be read by a copier scanner.

(When using high gloss paper)
(Relationship between image DUTY, density, and glossiness)
FIG. 21 is a graph showing the relationship between the image DUTY (toner amount) fixed on the sheet surface and the reflection density of the sheet surface on which the toner image is fixed. The vertical axis represents the reflection density. The horizontal axis indicates the image DUTY (toner amount) fixed on the sheet.

  FIG. 22 is a graph showing the relationship between the image DUTY (toner amount) fixed on the sheet surface and the gloss level of the sheet surface on which the toner image is fixed. The vertical axis represents the reflection density. The horizontal axis indicates the image DUTY (toner amount) fixed on the sheet.

Listed below are various conditions that are considered to affect the gloss of the sheet surface after fixing. The sheet used was gloss coated paper (157 g / m ^{2 of} SA Kinfuji + (trademark) manufactured by Oji Paper). Various conditions (process speed, nip pressure, etc.) that are considered to affect the gloss of the sheet surface after fixing are the same as those for low-gloss paper. Further, the controller K controls the image forming apparatus so that the amount of toner to be formed on the sheet is about 0.55 mg / cm ² when a signal having an image density of 100% is input.

  In addition, the controller K controls the image forming apparatus so that the surface temperature of the fixing roller is about 155 ° C., and the process speed at which the sheet passes through the fixing device is 95 mm / s.

  When an image including the original guarantee mark is formed, the process speed in the first image forming and fixing step, the temperature control temperature of the fixing roller, the process speed in the second image forming and fixing step, and the surface of the fixing roller It is possible to change the temperature control temperature. Even though it is easy for humans to recognize the contents of the original guarantee mark, it must be impossible for a copier scanner, so the foreground part and the background can be easily recognized by humans. It is desirable that there is a certain degree of gloss difference in the part. In this embodiment, the surface temperature of the first fixing roller is controlled to be about 155 ° C. and the process speed is 95 mm / s, and the surface temperature of the second fixing roller is 155 ° C. and the process speed is 285 mm / s. It was controlled to become.

  The toner used is a toner having a glass transition point (Tg) of about 55 ° C. using a polyester resin as described above.

  The conditions for creating the original guarantee mark in this embodiment are listed below.

Foreground image DUTY 10%
Process speed 285mm / s
Temperature control temperature 155 ℃
Background part Image DUTY 100%
Process speed 95mm / s
Temperature control temperature 155 ℃
On the other hand, FIGS. 23 and 24 show the first image forming and fixing process (here, the image forming and fixing process of the background portion of the original guarantee mark) in the image forming apparatus having the image characteristics as shown in FIGS. After that, the image DUTY (toner amount) and the toner image fixed on the sheet surface when the second image forming and fixing process (image forming and fixing process of the foreground portion of the original guarantee mark) is further performed thereon are fixed. It is a graph which shows the relationship between the reflection density and glossiness of the sheet | seat surface made. Note that the original guarantee mark used in this embodiment uses an image with an image DUTY (toner amount) of 100% in the background portion. FIGS. 23 and 24 show the image DUTY (toner amount) in the first image formation. ) Is the reflection density and glossiness for each image DUTY (toner amount) when the second image formation and fixing is performed after the 100% image is formed and fixed.

  As can be seen from FIGS. 23 and 24, when the foreground part image is fixed on the background part image (image DUTY 100%), it can be seen that the reflection density and the glossiness are changed. 25 and 26 are graphs in which the low image DUTY side of FIGS. 23 and 24 is enlarged. As described above, the original guarantee mark needs to be impossible for a copier scanner even if it is easy for a human to recognize the content portion. Table 2 shows the result of verifying whether the original guarantee is visible to humans or can be read by the copier scanner for each image DUTY in FIGS.

Visibility ○: The original guarantee mark can be visually confirmed.

X: The original guarantee mark cannot be visually confirmed.
Scanner ○: The original warranty mark cannot be read by the scanner.

  X: The original guarantee mark can be read by a scanner.

  In image formation when high gloss paper is used in this embodiment, the foreground image DUTY is set to 10%, so that the contents of the original guarantee mark can be recognized as shown in Table 2. Also, it cannot be read by a copier scanner.

<Example 2>
In the first embodiment, the background portion of the original guarantee mark is described as an image of the image DUTY 100%. However, when the image DUTY is different, the visibility of the original guarantee mark and the reading detection range by the scanner are different. In the present embodiment, a case where the background image DUTY is different will be described. Note that portions similar to those in the first embodiment can be used for portions relating to image formation and conveyance other than changing the image DUTY, and thus the description thereof is omitted.

(When using low gloss paper)
(Relationship between image DUTY, density, and glossiness)
In the image forming apparatus showing the relationship between the reflection density and the glossiness as shown in FIG. 15 and FIG. 157 g / m ² ), when the image DUTY is 80% in the background portion of the original guarantee mark, the image is formed so that the image DUTY in the foreground portion is 8%. Other conditions such as toner conditions, sheet conditions, image forming conditions, and fixing conditions are the same as those in the first embodiment.

  FIGS. 27 and 28 are diagrams after the first image forming and fixing process (here, the image forming and fixing process of the background portion of the original guarantee mark) in the image forming apparatus having the image characteristics as shown in FIGS. 15 and 16. Furthermore, the image DUTY (toner amount) and the toner image to be fixed on the sheet surface when the second image formation and fixing process (image formation fixing process of the foreground portion of the original guarantee mark) is further fixed thereon are fixed. It is a graph which shows the relationship between the reflection density of a sheet | seat surface, and glossiness. The original guarantee mark used in this embodiment uses an image with an image DUTY (toner amount) of 80% in the background portion. FIGS. 27 and 28 show the image DUTY (toner amount) in the first image formation. ) Is the reflection density and glossiness for each image DUTY (toner amount) when the second image formation and fixing are performed after the 80% image is formed and fixed.

  As can be seen from FIGS. 27 and 28, when the foreground part image is fixed on the background part image (image DUTY 80%), it can be seen that the reflection density and the glossiness change. 29 and 30 are graphs in which the low image DUTY side of FIGS. 27 and 28 is enlarged.

  As described above, the original guarantee mark needs to be impossible for a copier scanner even if it is easy for a human to recognize the content portion.

  Table 3 shows the result of verifying whether the original guarantee is visible to humans or can be read by the copier scanner for each image DUTY in FIGS. 29 and 30.

Visibility ○: The original guarantee mark can be visually confirmed.

X: The original guarantee mark cannot be visually confirmed.
Scanner ○: The original warranty mark cannot be read by the scanner.

  X: The original guarantee mark can be read by a scanner.

  In image formation using low-gloss paper in this embodiment, the foreground image DUTY is set to 8%, so that the contents of the original guarantee mark can be recognized as shown in Table 3. Also, it cannot be read by a copier scanner.

Next, in this embodiment, mat coated paper (157 g / m ² of Ulite (trademark) manufactured by Nippon Paper Industries Co., Ltd.), which is a low gloss paper, is used. The image was formed so that the image DUTY of the image was 5%. Other conditions such as other toner conditions, sheet conditions, image forming conditions, fixing conditions, and the like are the same as those in the first embodiment.

  FIG. 31 and FIG. 32 are diagrams after the first image forming and fixing process (here, the image forming and fixing process of the background portion of the original guarantee mark) in the image forming apparatus having the image characteristics as shown in FIG. 15 and FIG. Furthermore, the image DUTY (toner amount) and the toner image to be fixed on the sheet surface when the second image formation and fixing process (image formation fixing process of the foreground portion of the original guarantee mark) is further fixed thereon are fixed. It is a graph which shows the relationship between the reflection density of a sheet | seat surface, and glossiness. The original guarantee mark used in this embodiment uses an image with an image DUTY (toner amount) of 60% in the background portion. FIGS. 31 and 32 show the image DUTY (toner amount) in the first image formation. ) Represents the reflection density and glossiness for each image DUTY (toner amount) when the second image formation and fixing are performed after the 60% image is formed and fixed.

  As can be seen from FIGS. 31 and 32, when the foreground part image is fixed on the background part image (image DUTY 60%), it can be seen that the reflection density and the glossiness change. 33 and 34 are enlarged graphs of the low image DUTY side of FIGS. 31 and 32.

  As described above, the original guarantee mark needs to be impossible for a copier scanner even if it is easy for a human to recognize the content portion.

  Table 4 shows the results of verifying whether the original guarantee is visible to humans or can be read by the copier scanner for each image DUTY in FIGS.

Visibility ○: The original guarantee mark can be visually confirmed.

X: The original guarantee mark cannot be visually confirmed.
Scanner ○: The original warranty mark cannot be read by the scanner.

  X: The original guarantee mark can be read by a scanner.

  In image formation using low-gloss paper in this embodiment, the foreground image DUTY is set to 5%, so that the contents of the original guarantee mark can be recognized as shown in Table 4. Also, it cannot be read by a copier scanner.

(When using high gloss paper)
(Relationship between image DUTY, density, and glossiness)
In the image forming apparatus showing the relationship between the reflection density and the glossiness as shown in FIG. 21 and FIG. 22, in the second embodiment, gloss coated paper which is high gloss paper (SA Kinfuji + (trademark) manufactured by Oji Paper) 157 g / m ² ), when the image DUTY is 80% in the background portion of the original guarantee mark, the image is formed so that the image DUTY in the foreground portion is 8%. Other conditions such as other toner conditions, sheet conditions, image forming conditions, fixing conditions, and the like are the same as those in the first embodiment.

  FIG. 35 and FIG. 36 are diagrams after the first image forming and fixing process (here, image forming and fixing process of the background portion of the original guarantee mark) in the image forming apparatus having the image characteristics as shown in FIG. 21 and FIG. Furthermore, the image DUTY (toner amount) and the toner image to be fixed on the sheet surface when the second image formation and fixing process (image formation fixing process of the foreground portion of the original guarantee mark) is further fixed thereon are fixed. It is a graph which shows the relationship between the reflection density of a sheet | seat surface, and glossiness. The original guarantee mark used in this embodiment uses an image with an image DUTY (toner amount) of 80% in the background portion. FIGS. 35 and 36 show the image DUTY (toner amount) in the first image formation. ) Is the reflection density and glossiness for each image DUTY (toner amount) when the second image formation and fixing are performed after the 80% image is formed and fixed.

  As can be seen from FIGS. 35 and 36, when the foreground part image is fixed on the background part image (image DUTY 80%), it can be seen that the reflection density and the glossiness are changed. 37 and 38 are graphs in which the low image DUTY side of FIGS. 35 and 36 is enlarged.

  As described above, the original guarantee mark needs to be impossible for a copier scanner even if it is easy for a human to recognize the content portion.

  Table 5 shows the result of verifying whether the original guarantee is visible to humans or can be read by the copier scanner for each image DUTY in FIGS.

Visibility ○: The original guarantee mark can be visually confirmed.

X: The original guarantee mark cannot be visually confirmed.
Scanner ○: The original warranty mark cannot be read by the scanner.

  X: The original guarantee mark can be read by a scanner.

  In image formation when high gloss paper is used in this embodiment, the foreground image DUTY is set to 8%, so that the contents of the original guarantee mark can be recognized as shown in Table 5. Also, it cannot be read by a copier scanner.

Next, in Example 2, using gloss coated paper (157 g / m ^{2 of} SA Kinfuji + (trademark) manufactured by Oji Paper Co., Ltd.), which is high gloss paper, the image DUTY is 60% on the background portion of the original guarantee mark, The image was formed so that the background image DUTY was 5%. Other conditions such as other toner conditions, sheet conditions, image forming conditions, fixing conditions, and the like are the same as those in the first embodiment.

  FIGS. 39 and 40 show the image forming apparatus having the image characteristics shown in FIGS. 21 and 22 after the first image forming and fixing process (here, the image forming and fixing process of the background portion of the original guarantee mark). Furthermore, the image DUTY (toner amount) and the toner image to be fixed on the sheet surface when the second image formation and fixing process (image formation fixing process of the foreground portion of the original guarantee mark) is further fixed thereon are fixed. It is a graph which shows the relationship between the reflection density of a sheet | seat surface, and glossiness. The original guarantee mark used in this embodiment uses an image with an image DUTY (toner amount) of 60% in the background portion. FIGS. 39 and 40 show the image DUTY (toner amount) in the first image formation. ) Represents the reflection density and glossiness for each image DUTY (toner amount) when the second image formation and fixing are performed after the 60% image is formed and fixed.

  As can be seen from FIGS. 39 and 40, when the foreground part image is fixed on the background part image (image DUTY 60%), it can be seen that the reflection density and the glossiness are changed. 41 and 42 are graphs in which the low image DUTY side of FIGS. 39 and 40 is enlarged.

  As described above, the original guarantee mark needs to be impossible for a copier scanner even if it is easy for a human to recognize the content portion.

  Table 6 shows the result of verifying whether the original guarantee is visible to humans or can be read by the copier scanner for each image DUTY in FIGS. 39 and 40.

Visibility ○: The original guarantee mark can be visually confirmed.

X: The original guarantee mark cannot be visually confirmed.
Scanner ○: The original warranty mark cannot be read by the scanner.

  X: The original guarantee mark can be read by a scanner.

  In the image formation using the high gloss paper in this embodiment, the foreground image DUTY is set to 5%, so that the contents of the original guarantee mark can be recognized as shown in Table 4. Also, it cannot be read by a copier scanner.

  As described above, even if it is easy for a human to recognize the content portion by adjusting the image DUTY (toner amount) of the background portion and the foreground portion, it is impossible for the copier scanner. He explained that it is possible to create such original warranty marks. The relationship between the visibility of the background portion and the foreground portion and the scanner readability varies depending on the sheet on which the image is formed, environmental conditions, the type of toner used for image formation, the process speed, and the like. Therefore, it is assumed that the relationship between the toner amount used for control and the glossiness is stored in a ROM or HDD as a LUT (Look UP Table).

  In this way, the original guarantee mark can be adjusted to a desired shape and appearance at any place on the sheet by adjusting the image DUTY of the background portion and the foreground portion.

100 image forming apparatus, 1000 external input device, K controller

Claims (4)

An image processing device that performs predetermined image processing on an input image from an external device, and a uniformly charged image carrier surface is exposed based on the image data processed by the image processing device to form a latent image. An exposing unit to be formed, a developing unit that visualizes the latent image with a charge-holding toner by applying a predetermined developing bias, and the toner image to the recording medium directly or via an intermediate transfer member. An image forming step of forming an output image of an unfixed toner image on the recording medium by an image forming means comprising a transfer means for transferring;
Fixing the toner image transferred onto the recording medium, and forming an output image of the fixed toner image, and
On the first output image output by the first image output step that performs the fixing step after the image forming step, the final output image is again obtained by the second image output step that performs the image forming step and the fixing step. In an image forming apparatus provided with a multiple image forming and fixing step,
The gloss of the final output image is designated by the user from the operation unit or the control screen, and has a gloss area designation means capable of partially changing the gloss of the image area of the designated area, When it is designated by the glossiness area designation means so as to partially change the gloss of the image area of the designated area, after the first image formation and fixing other than the designated area and area, An image forming apparatus for performing image formation by forming and fixing a second image on the designated area.   When it is specified by the glossiness area specifying means that the gloss of the image area of the specified area is partially changed, the difference between the specified area and the other areas can be visually confirmed. The image forming apparatus according to claim 1, wherein the image forming apparatus cannot be read by a scanner.   The image forming apparatus according to claim 1, wherein a fixing condition in the first fixing step is different from a fixing condition in the second fixing step.   4. The image according to claim 1, wherein an amount of heat given to the toner image in the first fixing step is larger than an amount of heat given to the toner image in the second fixing step. 5. Forming equipment.