# Patent

## Title
Apparatus and method for forming an image on a recording medium using erasable material and non-erasable material

## Abstract

An image forming apparatus according to an embodiment comprises a first image forming section configured to form an image on a recording medium with a non-erasable material, and a second image forming section configured to form an image on the recording medium with an erasable material. The image forming apparatus further comprises a control section configured to separate image data according to attributes of the image data into first image data to be printed on the recording medium in the first image forming section and second image data to be printed on the recording medium in the second image forming section.

## Background
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of U.S. patent application Ser. No. 14/850,215, filed on Sep. 10, 2015, which is a division of U.S. patent application Ser. No. 13/964,926, filed on Aug. 12, 2013, the entire contents of which are incorporated herein by reference.


FIELD
Embodiments described herein relate to an image forming apparatus and method for forming an image with erasable and non-erasable material.
BACKGROUND
Image forming apparatuses for forming an image on a recording medium include an apparatus which comprises an image forming section using non-erasable toner and an image forming section using erasable toner in the same housing. On the other hand, the created image data is divided into a main body part and an additional part which are printed in different colors, and the user may desire to erase the color of the additional part later.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram illustrating a data communication system according to a first embodiment;
FIG. 2 is a diagram illustrating a printing condition screen of an MFP of a PC, according to the first embodiment;
FIG. 3 is a diagram illustrating the MFP, according to the first embodiment;
FIG. 4 is a block diagram illustrating a control system of the MFP, according to the first embodiment;
FIG. 5 is a function block diagram illustrating functions of the MFP, according to the first embodiment;
FIG. 6 is a diagram illustrating a structure of print data, according to the first embodiment;
FIG. 7 is a flowchart illustrating a separation and expanding processing of print data, according to the first embodiment;
FIG. 8 is a diagram illustrating the separation and expanding diagram of print data objects, according to the first embodiment;
FIG. 9 is a diagram illustrating an image transition, according to the first embodiment 1;
FIG. 10 is a diagram illustrating an MFP, according to a second embodiment;
FIG. 11 is a diagram illustrating the printing condition screen of the MFP of a PC, according to the second embodiment;
FIG. 12 is a block diagram illustrating a control system of the MFP, according to the second embodiment;
FIG. 13 is a block diagram illustrating functions of the MFP, according to the second embodiment;
FIG. 14 is a diagram illustrating a structure of print data, according to the second embodiment;
FIG. 15 is a flowchart illustrating a separation and expanding processing of print data, according to the second embodiment;
FIG. 16 is a diagram illustrating the separation and expanding diagram of print data objects, according to the second embodiment; and
FIG. 17 is a diagram illustrating an image transition, according to the second embodiment.



DETAILED DESCRIPTION
An image forming apparatus according to an embodiment comprises a first image forming section configured to form an image on a recording medium with a non-erasable material, and a second image forming section configured to form an image on the recording medium with an erasable material. The image forming apparatus further comprises a control section configured to separate image data according to attributes of the image data into first image data to be printed on the recording medium in the first image forming section and second image data to be printed on the recording medium in the second image forming section.
Embodiments are described below.
First Embodiment
The image forming apparatus of the first embodiment is described below with reference to accompanying drawings of FIG. 1-9. FIG. 1 illustrates an image forming system 100 according to embodiment 1. The image forming system 100 includes an MFP (Multi-Function Peripheral) 10 serving as an image forming apparatus comprising a PC (Personal Computer) 101 and a finisher 102 as user terminals. No limitation is given to the number or model of the user terminals and the image forming apparatuses. ALAN (Local Area Network) 103 connects the PC 101 with the MFP 10. The MFP 10 is capable of printing the print data, such as the file created by the PC 101, with a non-erasable material and/or an erasable material.
The PC 101 includes an application for the printing setting of the MFP 10. The printing setting application of the MFP 10 includes a printing condition screen for printing the created print data with an erasable material. For example, as shown in FIG. 2, a color selection condition 104a and an image designation condition 104b are displayed on the printing condition screen 104 for erasable printing. The creator of the print data or the system manager randomly checks the setting items of the color selection condition 104 and the image designation condition 104b, updates the next page if needed, and presets a printing condition of the print data for printing with erasable material.
The color selection condition 104a sets, for example, a red color or a blue color. For example, the color selection condition 104a is set to analyze the objects of the print data created by the PC and print the print data of which the characters are red or blue using an erasable material. Similarly, the image designation condition 104b may set a condition as follows: if the analyzed object is decorative words or a mark representing a graph or an annotation, then the analyzed object is printed with an erasable material. Decorative words include underline, boldface, italic, hatch and strikethrough. Further, the printing condition screen for erasable printing may be displayed on the operation screen of the MFP 10 directly and set using the operation panel of the MFP 10.
As shown in FIG. 3, the MFP 10 includes a CPU 120 serving as a control section for controlling the whole MFP 10. The MFP 10 includes a printing mode for forming an image on a sheet P serving as a recording medium and an erasing mode for erasing the image formed on the sheet P. The MFP 10 includes a printer section 11, a scanner section 12, a paper feed section 13 and a paper discharge section 22.
The MFP 10 also includes a control panel 50, which is provided with an operation panel 50a and a touch panel type display 50b. The operation panel 50a accepts an input of, for example, a user. The display 50b accepts the input of, for example, a user. The display 50b also generates and provides a display for the user.
The paper feed section 13 has a paper feed cassette 13a and a paper feed roller 15. The paper feed cassette 13a stores the sheet P. In the printing mode, the sheet P stored in the paper feed cassette 13a may be either unused sheets or reused sheets (i.e., sheet erased through an erasing processing). In the erasing mode, printed sheet P is stored in the paper feed cassette 13a. 
The printer section 11 includes a non-erasable printer section 11a serving as a first image forming section for forming an image with a non-erasable material and an erasing printer section 11b serving as a second image forming section for forming an image with an erasable material. The MFP 10 includes a conveyance path 23 in which sheet P is conveyed to the paper discharge section 22 after passing the non-erasable printer section 11a and the erasing printer section 11b from the paper feed section 13. The conveyance path 23 is provided with a conveyance roller 23a, a register roller 23b and a paper discharge roller 23c. 
The non-erasable printer section 11a is, for example, an electrophotographic type printer which forms an image with a non-erasable toner, that is, a non-erasable material which will not be thermally erased. The non-erasable printer section 11a is not limited to be an electrophotographic printer. The non-erasable printer section 11a includes a charger 16, an exposure scanning head 17, a developer 18 and a cleaner 21 around a photoconductive drum 14 rotating in the direction indicated by the arrow m. The charger 16 charges the photoconductive drum 14. The exposure scanning head 17 radiates exposure light towards the photoconductive drum 14 based on image data to form an electrostatic latent image on the photoconductive drum 14.
The developer 18 feeds a toner for the electrostatic latent image on the photoconductive drum 14. The developer 18 feeds non-erasable black toner for the electrostatic latent image on the photoconductive drum 14 with a two-component developing agent composed of the mixture of non-erasable black toner serving as a non-erasable material which will not be thermally erased and a magnetic carrier. A transfer device 20 transfers the toner image formed on the photoconductive drum 14 to the sheet P. The charger 16, the exposure scanning head 17, the developer 18 and the transfer device 20 constitute the first image forming section. The non-erasable printer section 11a may also be a color printer instead of a monochrome printer.
The MFP 10 includes a heater 24 along the conveyance path 23. If the MFP 10 is in the printing mode, the heater 24 functions as a fixing apparatus. If the MFP 10 is in the erasing mode, the heater 24 functions as an erasing apparatus. In the printing mode, the heater 24 heats and pressurizes the sheet P at a fixing temperature to fix the black toner image formed on the sheet P. In the erasing mode, the heater 24 heats and pressurizes the sheet P at an erasing temperature higher than the fixing temperature to erase the erasable image formed on the sheet P.
The CPU 120 controls the set temperature of the heater 24 according to whether the MFP 10 is in the printing mode or the erasing mode so as to change the set temperature. The CPU 120 may control the moving speed of the sheet P through the heater 24 according to whether the MFP 10 is in the printing mode or the erasing mode so as to change the moving speed.
The erasing printer section 11b is, for example, an inkjet type printer which forms an image with an erasable ink, that is, an erasable material that will be thermally erased. The erasing printer section 11b, which is not limited to be an inkjet type printer, may further be an electrophotographic printer for printing with an erasable toner. No limitation is given to the color or number of the erasable materials of the erasing printer section.
The erasing printer section 11b includes a first erasing printer section 31 and a second erasing printer section 32. The first erasing printer section 31 has a first ink cartridge 31a for storing, for example, red erasable ink and a first printing head 31b. The second erasing printer section 32 has a second ink cartridge 32a for storing, for example, blue erasable ink and a second printing head 32b. 
The color erasing printer section 11b includes a first platen roller 33 or a second platen roller 34 at a position opposite to the first erasing printer section 31 or the second erasing printer section 32 through the conveyance path 23.
The erasable ink, for example, will be erased if heated at a given temperature. No specific limitation is given to the color or specific material of the erasable ink as long as it will be thermally erased. The erasable ink is configured by properly combining a color generation compound such as leuko dye with a color developing agent, an erasing agent and a color changing temperature adjusting agent.
When the temperature of the color-erasable ink is below an erasing temperature, the color generation compound generates a color due to the effect of the color developing agent, thus making colors recognizable. When the erasable ink is heated above a specific erasing temperature, the color generation compound and the color developing agent are dissociated, thus making colors unrecognizable. The erasing temperature of the erasable ink is adjusted by designing materials of the color generation compound, the color developing agent, the color erasing agent and the color changing temperature adjusting agent. The erasable ink is erased at a temperature which is about, for example, 10 degrees centigrade above the fixing temperature of the non-erasable toner. For example, the erasing printer section 11b may change the erasing temperature by using red erasable ink and blue erasable ink.
The control system 60 of the MFP 10 taking an image printing control and an image color erasing control as the main job is illustrated below with reference to the block diagram shown in FIG. 4. The control system 60 includes a CPU 120, which controls the whole MFP 10, a storage section 61, and a calculating section 62. The control system 60 also includes a telephone line interface (I/F) 63 and a network I/F 64. The control system 60 further includes a control panel control circuit 66, a scanner control circuit 67, a non-erasable printer control circuit 70, an erasing printer control circuit 71 and a heater control circuit 72.
By executing the applications stored in the storage section 61, the CPU 120 realizes an image forming processing function using the non-erasable printer section 11a and an image forming processing function or image erasing processing function using the erasing printer section 11b. The storage section 61 includes a ROM (Read Only Memory) that stores applications for the control methods and control data for realizing basic actions of an image forming processing or an image erasing processing. The storage section 61 further includes a working memory for temporarily storing a printing condition for determining attributes of the print data created by the PC 101.
The storage section 61 stores the print data having attributes that are determined according to the printing condition. The storage section 61 includes a first area 61a serving as a non-erasable image storage section and a second area 61b and a third area 61c serving as erasable image storage sections.
The calculating section 62 includes a PDL (Page Description Language) analyzing section 62a for analyzing the object of the print data created by the PC 101. The calculating section 62 includes a separation and expanding section 62b for determining attributes of the object analyzed by the PDL analyzing section 62a and storing the expanded image data in the storage section 61. The CPU 120 stores the image data expanded by the separation and expanding section 62b in the first area 61a, the second area 61b and the third area 61c of the storage section 61, based on the determined attributes.
For example, the PDL analyzing section 62a analyzes attribute information by each object of the print data which is sent to the MFP 10 after being created by the PC 101.
The separation and expanding section 62b determines the analyzed print data by each object and separates the print data into first attribute data and second attribute data. The separation and expanding section 62b determines the print data created by the PC 101, that is, the image data not corresponding to the printing condition set on the printing condition screen 104 of the PC 101, to be first attribute data and stores the first attribute data in the first area 61a. For example, the separation and expanding section 62b determines monochromatic text data as first attribute data.
The separation and expanding section 62b determines the additional data in the print data created by the PC 101, that is, the image data corresponding to the printing condition set on the printing condition screen 104 of the PC 101, to be second attribute data and stores the second attribute data in the second area 61b and the third area 61c. Additional data includes, for example, decorative words (mark, underline, boldface, italic, hatch), a graph and an annotation.
The separation and expanding section 62b further determines whether or not the second attribute data is red or blue according to the printing condition.
The separation and expanding section 62b separates the red second attribute data from the print data created by the PC 101 and stores the red second attribute data in, for example, the second area 61b of the storage section 61 so that the second attribute data can be printed by the first erasing printer section 31. The separation and expanding section 62b separates the blue second attribute data from the print data created by the PC 101 and stores the blue second attribute data in, for example, the third area 61c of the storage section 61 so that the second attribute data can be printed by the second erasing printer section 32.
The telephone line interface (I/F) 63 communicates with a fax machine. The network I/F 64 communicates with a user terminal or another MFP. The control panel control circuit 66 controls an operation panel 50a and a display 50b. The scanner control circuit 67 controls a scanner section 12. The non-erasable printer control circuit 70 controls the non-erasable printer section 11a. The erasing printer control circuit 71 controls the erasing printer section 11b. 
The printing function of the MFP 10 is described with reference to the functional block diagram shown in FIG. 5. The MFP 10 includes an image data receiving section 64a for receiving print data from the network I/F 64, a PDL analyzing section 62a, a separation and expanding section 62b, a first area 61a, a second area 61b and a third area 61c. The MFP 10 also includes a non-erasable printer section 11a, a first erasing printer section 31, a second erasing printer section 32, a paper feed section 13, and a heater 24.
With the aforementioned functions, the MFP 10, when in the printing mode, prints image data on the sheet P fed from the paper feed section 13 using the non-erasable printer section 11a, the first erasing printer section 31 or the second erasing printer section 32. When in the erasing mode, the MFP 10 heats, using the heater 24, the sheet P fed from the paper feed section 13 at a temperature higher than an erasing temperature so as to erase the erasable image formed on the sheet P.
After receiving print data from the PC 101, the MFP 10 starts to print. The PC 101 instructs, using an application for the creation of files, a setting such as ‘print graphs in red color and underlines in blue color’ for a created file as a piece of printing attribute information. The MFP 10 enters the printing mode due to the starting of the print job, and the heater control circuit 72 sets the temperature of the heater 24 to be the fixing temperature of a black toner.
The MFP 10 analyzes objects using the PDL analyzing section 62a. As shown in FIG. 6, the PDL analyzing section 62a analyses print data 200 to decompose the print data into a header 201, an object (1) (underline) 202, object (2)-object (N) 203 and an object (N+1) 204. The content related to a print job is described in the header 201, and image data is described in the objects.
The separation and expanding section 62b of the MFP 10 separates and expands the objects of the print data 200 according to the flowchart of FIG. 7 and stores the separated and expanded objects in the first area 61a, the second area 61b or the third area 61c of the storage section 61. The separation and expanding section 62b acquires the attribute information analyzed by the PDL analyzing section 62a for each object (ACT 150).
For each expanded object of the print data 200, the separation and expanding section 62b determines whether or not the object acquired is a graph (ACT151). If the object is not a graph (No in ACT 151), the flow proceeds to ACT 152 to determine whether or not the object is decorative words. If it is determined in ACT 152 that the object is not decorative words (No in ACT 152), the flow proceeds to ACT 153 to determine whether or not the object is an annotation. If it is determined in ACT 153 that the object is not an annotation (No in ACT 153), the flow proceeds to ACT 154 to determine whether or not the object is colored. If it is determined in ACT 154 that the object is not colorized (No in ACT 154), then it is determined that the object is monochromatic text data, the flow proceeds to ACT 160 to store the expanded image data in the first area 61a as first attribute data. The separation and expanding section 62b determines that the objects (2)-(N) 203 of the print data 200 are text data and stores the image data of the objects in the first area 61a. 
If the object is not first attribute data, that is, the acquired object is a graph (Yes in ACT 151) or decorative words (Yes in ACT 152) or annotation (Yes in ACT 153) or is colored (Yes in ACT 154), then it is determined that the object is second attribute data, then the flow proceeds to ACT 156.
The separation and expanding section 62b determines whether or not the object of second attribute data is set to be red. If the object is set to be red (Yes in ACT 156) on the printing condition screen 104 of the PC 101, the separation and expanding section 62b proceeds to ACT 161 to store the expanded image data in the second area 61b. If the object is set to be blue (No in ACT 156) on the printing condition screen 104 of the PC 101, the separation and expanding section 62b proceeds to ACT 162 to store the expanded image data in the third area 61c. The separation and expanding section 62b determines that the object N+1 (graph) 204 of the print data 200 is to be printed as red additional data and that the object (1) (underline) 202 of the print data 200 is to be printed as blue additional data.
When reaching the last page (Yes in ACT 170), the separation and expanding section 62b ends the separation and expanding processing of the print data 200. In the flowchart of FIG. 7, the determination items change according to the printing condition set on the printing condition screen 104 of the PC 101.
FIG. 8 is a diagram illustrating the separation and expanding of the print data 200. The print data 200 shown in FIG. 8(a) is expanded and separated into the objects (2)-(N) 203 shown in FIG. 8 (b), the object (N+1) (graph) 204 shown in FIG. 8 (c) and the object (1) (underline) 202 shown in FIG. 8 (d).
The MFP 10 prints the objects (2)-(N) 203 stored in the first area 61a with non-erasable black toner, the object (N+1) (graph) 204 stored in the second area 61b with red erasable ink, and the object (1) (underline) 202 stored in the third area 61c with blue erasable ink.
The MFP 10 forms, on the sheet P conveyed by the conveyance path 23, black toner images corresponding to the objects 2N 203 using the non-erasable printer section 11a. The MFP 10 heats, using the heater 24, and fixes the black toner images on the sheet P. Next, the MFP 10 prints, on the sheet P conveyed by the conveyance path 23, the image of the object N+1 (graph) 204 using the first erasing printer section 31. Sequentially, the MFP 10 prints, on the sheet P conveyed by the conveyance path 23, the image of the object 1 (underline) 202 using the second erasing printer section 32. When conveyed on the conveyance path 23 of the MFP 10, the sheet P is printed with images corresponding to the print data 200 by the non-erasable printer section 11a, the first erasing printer section 31 and the second erasing printer section 32.
FIG. 9(a) is a diagram illustrating an image printed on the sheet P. A file 203a formed with non-erasable black toner, a graph 204a formed with red erasable ink and an underline 202a formed with blue erasable ink are printed on the sheet P. The user or the system manager may set a printing condition for the use of erasable ink on the printing condition screen 104 of the PC 101 freely.
The graph 204a and the underline 202a printed in the image on the sheet P are erasable. The graph 204a and the underline 202a, if so desired, can be erased by the user using the MFP 10. The user places the printed sheet P in the paper feed section 13 and switches the MFP 10 to be in an erasing mode. When in the color erasing mode, the heater control circuit 72 sets the temperature of the heater 24 to be an erasing temperature.
After starting an erasing processing, the MFP 10 heats the sheet P acquired from the paper feed section 13 and conveyed in the conveyance path 23 at an erasing temperature using the heater 24 and then discharges the sheet P to the paper discharge section 22. By heating the sheet P at the erasing temperature, the graph 204a and the underline 202a printed on the sheet P are erased. As shown in FIG. 9 (b), needless graph 204a and underline 202a are erased so that only the file 203a on the sheet P is readable.
The MFP 10 may be used for any purpose, for example, to print the grids of a form with an erasable material and erase the grids after necessary items are recorded, but is not limited to be used for a specific purpose.
In accordance with the first embodiment, the MFP 10 includes a non-erasable printer section 11a and an erasing printer section 11b. The MFP 10 prints a file 203a formed with non-erasable black toner, a graph 204a formed with red erasable ink and an underline 202a formed with blue erasable ink on the sheet P. Unwanted graph 204a and underline 202a are erased after being printed so that only the header 201 and the file 203a formed on the sheet P with black toner are readable.
According to embodiment 1, the printed images including an image printed with non-erasable black toner and an image printed with red and blue erasable ink needed by the user are acquired during a printing processing. By changing colors of the erasable material and the non-erasable material, the printed images can be read easily. The erasable material can be erased after a print job so that only the image formed with the non-erasable material can be read, thereby acquiring a printed image which can be read easily and used effectively according to a use purpose.
Second Embodiment
The image forming apparatus of a second embodiment is described below with reference to accompanying drawings of FIG. 10-17. In the second embodiment, similar to the first embodiment, the color erasing printer section is further provided with an electrophotographic color erasing printer. The configuration of the second embodiment that is the same as that described in embodiment 1 is denoted by the same reference numbers and is therefore not described herein in detail.
As shown in FIG. 10, the MFP 80 includes, along the conveyance path 23, a third erasing printer section 81 of electrophotographic type serving as an erasable image forming apparatus forming an image with erasable black toner at the downstream side of the non-erasable printer section 11a. The third erasing printer section 81 is the same as the non-erasable printer section 11a except that the toner used by the developer 81a is different from that used by the non-erasable printer section 11a. 
The erasable black toner is erased, for example, when heated at an erasing temperature. In the second embodiment, the erasing temperature of the erasable black toner is set to be higher than that of the red erasable ink of the first erasing printer section 31 and the blue erasable ink of the second erasing printer section 32. The fixing temperature of the erasable black toner is, for example, the same as that of the non-erasable black toner. The erasable black toner may be erased when heated at a relatively high temperature, such as 20 degrees centigrade above the fixing temperature.
When in the erasing mode, the heater control circuit 72 of the MFP 80 may set the erasing temperature of the heater 24 to be equal to the erasing temperature of ink or equal to the erasing temperature of toner (which is higher than the erasing temperature of ink). The erasing temperature of ink refers to a temperature at which the red and blue erasable inks are erased. The erasing temperature of the toner refers to a temperature at which the erasable black toner is erased.
The PC 101 includes the printing condition screen 105 shown in FIG. 11 for the printing setting of the MFP 80. The color selection condition 105a of the printing condition screen 105 sets red, blue and black colors. The image designation condition 105b sets decorative words, a graph, an annotation and a bordered text. Further, the printing condition screen may be displayed on the operation screen of the MFP 10 directly and set using the operation panel of the MFP 10.
As shown in FIG. 12, the storage section 82 of the control system 83 of the MFP 80 includes a first area 82a serving as a non-erasable storage section, a second area 82b serving as an erasable storage section, a third area 82c and a fourth area 82d. The data printed by the non-erasable printer section 11a is stored in the first area 82a. The data printed by the first erasing printer section 31 is stored in the second area 82b. The data printed by the second erasing printer section 32 is stored in the third area 82c. The data printed by the third erasing printer section 81 is stored in the fourth area 82d. 
As shown in the functional block diagram of FIG. 13, the MFP 80 includes a first area 82a, a second area 82b, a third area 82c, a fourth area 82d, a non-erasable printer section 11a, a first erasing printer section 31, a second erasing printer section 32 and a third erasing printer section 81.
With the aforementioned functions, the MFP 80, when in a printing mode, prints image data on the sheet P fed from the paper feed section 13 using the non-erasable printer section 11a, the first erasing printer section 31, the second erasing printer section 32 or the third erasing printer section 81.
After receiving print data from the PC 101, the MFP 80 starts to print. The PC 101 instructs, using an application for the creation of files, a setting such as ‘add a border at a specified file position, print graphs in red color and underlines in blue color’ for a created file including printing attribute information. The MFP 80 enters the printing mode due to the starting of the print job, and the heater control circuit 72 sets the temperature of the heater 24 to be the fixing temperature of a black toner.
The MFP 80 analyzes objects of the print data using the PDL analyzing section 62a. As shown in FIG. 14, the PDL analyzing section 62a analyzes print data 210 to separates the print data into a header 201, an object (1) 202, objects (2)-(N) 203, an object (N+1) (graph) 204 and an object (N+2) (bordered text) 206. The content related to a print job is described in the header 201, and image data is described in the objects.
The separation and expanding section 62b of the MFP 80 separates and expands the objects of the print data 210 according to the flowchart of FIG. 15 and stores the separated and expanded objects in the first area 82a, the second area 82b, the third area 82c or the fourth area 82d of the storage section 82. The flowchart shown in FIG. 15 of embodiment 2 is different from that shown in FIG. 7 of embodiment 1 in that a determination on whether or not the print data is a bordered text should be made if the print data is file data.
If the result of ACT 153 described in the first embodiment is No—that is, the object is text data—then in the second embodiment, it is determined in ACT 154 whether or not the object is a bordered text. Moreover, when the object is not a bordered text (No in ACT 154), it is determined in ACT 155 whether or not the object is colored. If it is determined in ACT 155 that the object is not colored (No in ACT 155), then it is determined that the object is monochromatic text data, the flow proceeds to ACT 160 to store the image data in the first area 82a as first attribute data.
If the object is a graph, decorative words, an annotation, a bordered text or is colored (Yes in ACT152, ACT153, ACT154 or ACT155), then it is determined that the object is second attribute data, consequentially, the flow proceeds to ACT 156 to determine whether or not the object of the second attribute date is red. In ACT 161, the object (N+1) (graph) 204 is expanded into image data and is then stored in the second area 82b. If the object of the second attribute data is not red (No in ACT 156), the flow proceeds to ACT 157 to determine whether or not the object of the second attribute data is blue. In ACT 162, the object 1 (underline) 202 is expanded into image data and is then stored in the third area 82c. If the object of the second attribute date is not blue (No in ACT 157), the object (N+2) (bordered text) 206 is expanded into image data and is then stored in the fourth area 82d in ACT163.
FIG. 16 is a diagram illustrating the separation and expanding of the print data 210. The print data 210 shown in FIG. 16(a) is expanded and separated into the objects (2)-(N) 203 shown in FIG. 16(b), the object (N+1) (graph) 204 shown in FIG. 16(c), the object (1) (underline) 202 shown in FIG. 16(d) and the object (N+2) (bordered text) 206 shown in FIG. 16 (e).
The MFP 80 prints images of the objects (2)-(N) 203 stored in the first area 82a with non-erasable black toner. The MFP 80 prints the image of the object (N+1) (graph) 204 stored in the second area 82b with red erasable ink, the image of the object (1) (underline) 202 stored in the third area 82c with blue erasable ink, and the image of the object (N+2) (bordered text) 206 stored in the fourth area 82d with erasable black toner.
The MFP 80 forms, on the sheet P conveyed by the conveyance path 23, non-erasable black toner images corresponding to the objects (2)-(N) 203 using the non-erasable printer section 11a. The MFP 80 forms, on the sheet P on which the non-erasable black toner image is formed, an erasable black toner image corresponding to the object (N+2) (bordered text) 206 using the third erasing printer section 81. The MFP 80 heats, using the heater 24, and fixes the non-erasable black toner image and the erasable black toner image on the sheet P.
Next, the MFP 80 prints, on the sheet P conveyed by the conveyance path 23, the object (N+1) (graph) 204 of the image data using the first non-erasable printer section 31. Then, the MFP 80 prints, on the sheet P conveyed by the conveyance path 23, the object (1) (underline) 202 of the image data using the second erasing printer section 32. When conveyed on the conveyance path 23 of the MFP 80, the sheet P is printed with images corresponding to the print data 210 by the non-erasable printer section 11a, the third erasing printer section 81, the first erasing printer section 31 and the second erasing printer section 32.
FIG. 17(a) is a diagram illustrating an image printed on the sheet P. A file 203a formed with non-erasable black toner, a bordered text 206a formed with erasable black toner, a graph 204a formed with red erasable ink and an underline 202a formed with blue erasable ink are printed on the sheet P.
The bordered text 206a, the graph 204a and the underline 202a printed in the image on the sheet P are erasable. As the erasing temperature of the erasable black toner, the red ink and the blue ink are different, the graph 204a and the underline 202a may be erased while the bordered text 206a is not erased.
The graph 204a and the underline 202a, if determined to be unnecessary, can be erased by switching the MFP 80 to an erasing mode in which the heater 24 is set at the erasing temperature of ink. As shown in FIG. 17 (b), needless graph 204a and underline 202a are erased so that only the header 201, the file 203a and the bordered text 206a on the sheet P are readable.
The bordered text 206a, if needless, can be erased by switching the MFP 80 to the erasing mode in which the heater 24 is set at the erasing temperature of toner. As shown in FIG. 17 (c), the needless bordered text 206a is erased so that only the header 201 and the file 203a on the sheet P are readable. And the graph 204a, the underline 202a and the bordered text 206a on the sheet P can be erased synchronously after a print job is finished.
No limitation is given to the use of the MFP 80. For example, it may be set that the files created by the PC 101 are all bordered text which are printed with erasable black toner, and that decorative words are printed with erasable ink. If files are all printed with erasable black toner, needless files may be erased after needless decorative words on the sheet are erased. Alternatively, all files and decorative words may be erased so as to reuse the sheet.
In accordance with the second embodiment, in addition to the erasing printer section 11b, the first erasing printer section 31 and the second erasing printer section 32, the MFP 80 further includes a third erasing printer section 81. The erasing temperature of the erasable black toner of the third erasing printer section 81 is set to be higher than the erasing temperature of the erasable ink. The MFP 80 prints a file 203a with non-erasable black toner, a graph 204a with red erasable ink, an underline 202a with blue erasable ink and a bordered text 206a with erasable black toner on the sheet P. Needless graph 204a, underline 202a and bordered text 206a may be erased after a print job.
Similar to the first embodiment, in the second embodiment, the printed image needed by the user may be acquired during the printing processing and the erasable printed image is erased after the print job so as to acquire the printed image that can be read easily and used effectively according to a desired purpose. Moreover, erasable printed images may be erased at the erasing temperature of each erasable material so as to acquire the printed image needed by the user.
According to at least one of the embodiments above, parts of images are erased after the printed images needed by the user are acquired. Thus, the printed image that can be read easily and used effectively are acquired according to a desired purpose.
The image forming apparatus described in at least one of the aforementioned embodiments is not limited to have an image printing function and an image erasing function. For example, the image forming apparatus, if provided with a function of printing with a non-erasable material and a function of printing with an erasable material, may have no erasing function. If the image forming apparatus only has a printing function, then another image erasing apparatus different from the image forming apparatus is used to erase the image formed with an erasable material.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the invention. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention.

## Claims

1. An image forming apparatus, comprising:
a first image forming unit configured to form an image with a first material, which is non-erasable;
a second image forming unit configured to form an image with a second material, which is erasable; and
a control unit configured to control the first image forming unit to print a first type of image on a medium with the first material and control the second image forming unit to print a second type of image on the medium with the second material, based on selections made on an input interface to print the first type of image with a color of the first material and the second type of image with a color of the second material,
wherein the first type of image is one of decorative characters, annotations, and bordered characters, and the second type of image is different from the first type of image.

2. The image forming apparatus according to claim 1, further comprising:
a third image forming unit configured to form an image with a third material, which is erasable and has a color and an erasing temperature different from those of the second material, wherein
the control unit is further configured to control the third image forming unit to print a third type of image on the medium with the third material.

3. The image forming apparatus according to claim 1, wherein the second material is erasable by heating at or above an erasing temperature thereof.

4. The image forming apparatus according to claim 3, wherein the second image forming unit comprises a plurality of color-erasable image forming units of which the color-erasable materials are different in color erasing temperature.

5. The image forming apparatus according to claim 3, wherein the erasing temperature is higher than a fixing temperature at which the first material is fixed to the medium.

6. The image forming apparatus according to claim 1, wherein the control unit is further configured to store first image data corresponding to the first type of image in a first storage section and second image data corresponding to the second type of image in a second storage section.

7. The image forming apparatus according to claim 1, wherein the first material has a color different from a color of the second material.

8. The image forming apparatus according to claim 1, further comprising:
an operation panel that displays the input interface and through which the selections are made.

9. The image forming apparatus according to claim 1, wherein the selections are made using a computing device connected to the image forming apparatus over a network.

10. A method of forming an image containing a first type of image and a second type of image on a medium, comprising:
determining from selections made on an input interface that the first type of image is to be printed with a non-erasable material and the second type of image is to be printed with a first erasable material;
printing the first type of image on the medium with the non-erasable material; and
printing the second type of image on the medium with the first erasable material,
wherein the first type of image is one of decorative characters, annotations, and bordered characters, and the second type of image is different from the first type of image.

11. The method according to claim 10, further comprising:
printing a third type of image with a second erasable material having a color different from a color of the first erasable material.

12. The method according to claim 11, wherein the first erasable material is erasable by heating to at least a first erasing temperature, and the second erasable material is erasable by heating to at least a second erasing temperature different from the first erasing temperature.

13. The method according to claim 10, wherein a color of the erasable material is different from a color of the non-erasable material.

14. The method according to claim 10, further comprising
erasing the second type of image by heating the medium to an erasing temperature of the first erasable material or higher.

15. The method according to claim 14, wherein the erasing temperature of the first erasable material is higher than a fixing temperature at which the non-erasable material is fixed to the medium.

16. The method according to claim 10, further comprising:
storing first image data corresponding to the first type of image in a first storage section; and
storing second image data corresponding to the second type of image in a second storage section.

17. The method according to claim 10, further comprising:
displaying the input interface on an operation panel; and
determining the selections based on inputs made through the operation panel.

18. The method according to claim 10, wherein the selections are received over a network from a computing device having the input interface and through which the selections are made.