Patent Publication Number: US-8976211-B2

Title: Image forming apparatus, erasing device, image erasing system, and consumable

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of U.S. Provisional Application No. 61/500,357, filed on Jun. 23, 2011; the entire contents of which are incorporated herein by reference. 
    
    
     FIELD 
     Embodiments described herein relate generally to an image forming apparatus, an erasing device, an image erasing system, and a consumable. 
     BACKGROUND 
     It is a general practice to print information on paper and check the information using an image forming apparatus such as an MFP (Multi Function Peripheral). A quantity of use of paper increases according to an increase in an information amount. 
     However, most of prints printed in this way are not required to be preserved and are temporarily recorded and discarded in a short period. Because of increasing awareness of environmental issues such as protection of forest resources, which are paper raw materials, and a reduction in carbon dioxide emission, use of reverse side paper, duplex printing, use of recycled paper, and the like are commonly performed. Further, as a method of enabling repeated use of paper, there are known a method of mechanically or chemically peeling an image forming material (e.g., a toner) on paper and a method of using an erasable toner, which is erased by heat, light, a chemical, or the like, for printing. 
     Printing and erasing with the erasable toner are repeated to realize protection of forest resources and a reduction in carbon dioxide emission using paper plural times. If an erasable toner, which is erased by heat, is used, in some cases, erasing temperature varies and erasing unevenness occurs because of variations in raw materials of the erasable toner. Therefore, the erasing temperature of an erasing device is often set rather high. As a result, a paper curl, the shine or gloss of an erasing mark, high-temperature offset, and the like sometimes occur. On the other hand, if the erasing temperature of the erasing device is set rather low, erasing unevenness sometimes occurs to deteriorate visibility when printing is performed next time using erased paper. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exemplary perspective view of a schematic shape of an MFP according to a first embodiment; 
         FIG. 2  is an exemplary schematic configuration diagram of the MFP according to the first embodiment; 
         FIG. 3  is an exemplary configuration diagram of an example of the configuration of a process unit of the MFP according to the first embodiment; 
         FIG. 4  is another exemplary schematic configuration diagram of the MFP according to the first embodiment; 
         FIG. 5  is an exemplary diagram of a connection state of the configuration of a control system of the MFP according to the first embodiment and external apparatuses; 
         FIG. 6  is an exemplary flowchart for explaining an operation procedure concerning erasing by the MFP according to the first embodiment; 
         FIG. 7  is an exemplary flowchart for explaining an operation procedure concerning erasing by an erasing device according to the first embodiment; 
         FIG. 8  is an exemplary flowchart for explaining an operation procedure concerning erasing by an MFP according to a second embodiment; 
         FIG. 9  is an exemplary flowchart for explaining an operation procedure concerning erasing by an erasing device according to the second embodiment; 
         FIG. 10  is an exemplary diagram of a form of information formed in an image by the MFP according to the second embodiment; 
         FIG. 11  is an exemplary flowchart for explaining an operation procedure concerning erasing by an MFP according to a third embodiment; and 
         FIG. 12  is an exemplary flowchart for explaining an operation procedure concerning erasing by an erasing device according to the third embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In general, according to one embodiment, an image forming apparatus that forms an image on a medium includes: an image forming material erasable by heat; a storage medium having stored therein information concerning temperature for heating the image forming material; and a controller configured to control an image forming operation on the basis of the information concerning the temperature stored in the storage medium. The information concerning the temperature includes forming temperature, which is temperature for heating the image forming material during image formation, and erasing temperature, which is temperature for heating the image forming material during image erasing. 
     First Embodiment 
     An MFP (Multi Function Peripheral), which is an image forming apparatus of an electrophotographic system, is explained below as an example of an image forming apparatus according to an embodiment of the present invention. The MFP is a digital compound machine not only for scanning, reading, and copying an image at designated resolution and in a designated sheet size but also for comprehensively utilizing various functions of office equipment such as an image receiving function by facsimile, an image receiving function by E-mail, and a printed image receiving function by network. 
       FIG. 1  is an exemplary perspective view of a schematic shape of an image forming apparatus according to a first embodiment. 
     An MFP  201  includes a print section  1 , a sheet tray  3 , a scan section  5 , an auto-feed section  7 , and an operation panel  9 . 
     The print section  1  outputs image information as an output image called, for example, hardcopy or printout. The sheet tray  3  feeds a medium, which is a sheet of an arbitrary size, used for image output to the print section  1 . The scan section  5  captures image information from an original document as image data. The auto-feed section  7  delivers the original document, for which reading ends, from a reading position to a discharge position and leads the next original document to the reading position. The operation panel  9  is an instruction input section for instructing operations of the MFP  201  such as the start of image formation in the print section  1  and the start of reading of image information of an original document by the scan section  5 . The operation panel  9  includes a display section  8 , which includes an LCD (Liquid Crystal Device), for receiving the input of an instruction and displaying information to an operator. 
     Further, the MFP  201  can be connected to a not-shown network or communication line and receive image data by facsimile or E-mail. 
     An image forming operation in the image forming apparatus is explained. 
       FIG. 2  is an exemplary schematic configuration diagram of the image forming apparatus according to the first embodiment. The MFP  201  is an image forming apparatus in which a multiple tandem process is used. The MFP  201  includes a multiple tandem process  20 , a blade  12  (a toner removing section), a control device  14 , a paper feeding device  15 , a primary transfer belt  16 , a secondary transfer roller  17 , and a fixing device  18 . The multiple tandem process  20  includes four process units  21 ,  22 ,  23 , and  24 . 
       FIG. 3  is an exemplary configuration diagram of an example of the configuration of the process unit  21  of the image forming apparatus according to the first embodiment. The process unit  21  includes a developing device  21   a , a photoconductive drum  21   b , a charging device  21   c , and an exposing device  21   d.    
     In the process unit  21 , the photoconductive drum  21   b  (an image bearing member) is charged to predetermined potential by the charging device  21   c . A laser beam intensity-modulated according to image information is irradiated on the photoconductive drum  21   b  by the exposing device  21   d . Consequently, an electrostatic latent image corresponding to an image, which should be output, is formed on the photoconductive drum  21   b . The electrostatic latent image formed on the photoconductive drum  21   b  is selectively provided with a toner by a magnetic brush of the developing device  21   a  and developed. A developed toner image on the photoconductive drum  21   b  is transferred onto the primary transfer belt  16  by an electric field. The process unit  21  is a cleaner-less type. However, the process unit  21  is not limited to this type and may include a cleaner. The configuration and the operation of the other process units  22 ,  23 , and  24  are the same as above. 
     The process units  21 ,  22 ,  23 , and  24  may use plural erasable toners having colors different from one another or may use at least one erasable toner. 
     A bond of a coloring matter and a color developing agent of the erasable toner is cut off by heat, whereby erasing is performed. For the erasing of a toner image, it is necessary to heat a sheet at temperature equal to or higher than predetermined temperature, for example, at 120° C. to 150° C. 
     In the MFP  201  shown in  FIG. 2 , respective color toner images are transferred onto the primary transfer belt  16  through an image forming process by the process units  21 ,  22 ,  23 , and  24 . Thereafter, a sheet is fed and discharged from the MFP  201  through a secondary transfer process by the secondary transfer roller  17  and a fixing process by the fixing device  18 . 
     The MFP  201  is not limited to the configuration shown in  FIG. 2  and may have a configuration shown in  FIG. 4 . The MFP  201  shown in  FIG. 4  includes a multiple tandem process  40  instead of the multiple tandem process  20 . The multiple tandem process  40  includes, for example, a process unit  41  that uses an erasable toner and process units  42 ,  43 ,  44 , and  45  that use unerasable toners of four colors. 
       FIG. 5  is an exemplary diagram of a connection state of the configuration of a control system of the MFP  201  according to the first embodiment and external apparatuses. 
     The MFP  201  includes five CPUs (Central Processing Units), i.e., a main CPU  4   a  in the main control section  4 , a scanner CPU  5   a  of the scan section  5 , a printer CPU  1   a  of the print section  1 , a panel CPU  9   a  of the operation panel  9 , and a communication control CPU  6   a  of a communication control section  6 . 
     The main CPU  4   a  collectively controls the MFP  201 . The main control section  4  includes a storage device  4   b . A computer program for controlling the operation of the MFP  201 , image information, and the like are stored in the storage device  4   b.    
     The main CPU  4   a  performs bidirectional communication with the printer CPU  1   a  via a shared RAM (Random Access Memory). The main CPU  4   a  outputs an operation instruction. The printer CPU  1   a  returns a status of the state of the print section  1 . The printer CPU  1   a  and the scanner CPU  5   a  exchange information through serial communication. The printer CPU  1   a  outputs an operation instruction. The scanner CPU  5   a  returns a status of the state of the scan section  5 . 
     The operation panel  9  includes the display section  8  including the touch panel as explained above, an operation section  10  including various operation keys, and the panel CPU  9   a  connected to the display section  8  and the operation section  10 . The panel CPU  9   a  is connected to the main CPU  4   a  and performs exchange of information. 
     The communication control CPU  6   a  is an interface that performs exchange of information with plural PCs (Personal Computers)  51   a  to  51   b , which are external apparatuses, and an erasing device  60  via a router  50 . The main CPU  4   a  is connected to the communication control CPU  6   a  and exchanges information with the external apparatuses. In an example explained herein, the information is exchanged by wire. However, it goes without saying that the information may be exchanged by radio using an electromagnetic wave. 
     The MFP  201  includes a consumable including a storage medium  33 . Further, the MFP  201  includes a reading section  30  that reads out information from the storage medium  33 . The reading section  30  is a contact type or a noncontact type according to the type of the storage medium  33 . In  FIG. 5 , a toner  34  including the storage medium  33  is disclosed as an example of the consumable. The erasable toner  34  used in the MFP  201  has a characteristic that the erasable toner  34  is fixed at 95° C. and erased or otherwise decolorized at 110° C. However, both of the fixing temperature and the erasing temperature have variations according to variations in toner raw materials and variations in manufacturing conditions. The printer CPU  1   a  of the print section  1  reads information of the storage medium  33  via the reading section  30 , transmits the information to the main CPU  4   a , and controls the fixing device  18  on the basis of the information. 
     The consumable is not limited to the toner  34  and may be a toner cartridge. The storage medium  33  may be configured using an IC chip, an RFID (Radio Frequency IDentification), or the like and may be a barcode or a QR code. 
     The erasing device  60 , which is the external apparatus, includes a reading section  61 , an erasing section  62 , a main control section  63 , and a communication control section  64 . The erasing section  62  heats and erases an image formed on a sheet with an erasable toner. The reading section  61  reads information concerning the erasable toner printed on the sheet (details are explained later). The communication control section  64  performs exchange of information with the MFP  201  via a communication control CPU  64   a . A main CPU  63   a  of the main control section  63  collectively controls the sections of the erasing device  60 . A storage device  63   b  stores information related to a control operation of the main control section  63 . 
     A cooperated operation concerning erasing by the MFP  201  and the erasing device  60  according to the first embodiment is explained. 
       FIG. 6  is an exemplary flowchart for explaining an operation procedure concerning erasing by the MFP  201  according to the first embodiment. 
     An operation start button for the MFP  201  is operated on the operation panel  9 , in Act  01 , the main control section  4  detects that the consumable for erasing (the toner)  34  is present. In Act  02 , the printer CPU  1   a  detects whether the storage medium  33  is present in a predetermined position of the toner  34 . 
     If the printer CPU  1   a  detects that the storage medium  33  is present (YES in Act  02 ), the printer CPU  1   a  reads information concerning erasing of the toner  34  stored in the storage medium  33 . The information concerning erasing includes erasing temperature, fixing temperature, and the like of the erasable toner. 
     In Act  03 , the printer CPU  1   a  reads the information concerning the erasing temperature of the erasable toner. In Act  04 , the main CPU  4   a  stores the read information concerning the erasing temperature of the erasable toner in the storage device  4   b . The main CPU  4   a  transmits the read information concerning the erasing temperature to the erasing device  60  in response to a request from the erasing device  60 . The main CPU  4   a  does not always transmit the read information concerning the erasing temperature in response to the request from the erasing device  60 . The main CPU  4   a  may periodically transmit the read information concerning the erasing temperature to the erasing device  60 . 
     On the other hand, in Act  05 , the printer CPU  1   a  reads the information concerning the fixing temperature of the erasable toner. In Act  06 , the printer CPU  1   a  controls, on the basis of the read information concerning the fixing temperature, fixing temperature during printing with the toner  34  and obtains an image in an optimum fixed state. In Act  08 , the fixing device  18  discharges a sheet on which the image is printed. 
     If the printer CPU  1   a  detects that the storage medium  33  is absent (NO in Act  02 ), in Act  07 , the printer CPU  1   a  controls the fixing temperature to temperature determined in advance. In Act  08 , the fixing device  18  discharges a sheet on which an image is printed. If information in the storage medium  33  may not be able to be read because of some reason even if the storage medium  33  is present, the MFP  201  performs operation same as the operation performed when the storage medium  33  is not present. The information in the storage medium  33  may not be able to be read, for example, if data in the storage medium  33  is broken or lost or if the information concerning the fixing temperature and the erasing temperature, which should be written in the storage medium  33 , is not written in the storage medium  33  during manufacturing of the toner  34 . 
     If the fixing temperature is controlled to the temperature determined in advance, naturally, since the fixing operation is not performed at temperature optimum for the toner  34 , fixability could be deteriorated. The information concerning the erasing temperature is not transmitted to the erasing device  60 . 
     The image formed on the sheet using the erasable toner is erased by the erasing device  60  after the image finishes a desired role. 
       FIG. 7  is an exemplary flowchart for explaining an operation procedure concerning erasing by the erasing device  60  according to the first embodiment. 
     When an erasing operation for an image to be erased is started, in Act  11 , the main CPU  63   a  starts reception of a sheet on which the image to be erased is printed. In Act  12 , the main CPU  63   a  requests, via the communication control CPU  64   a , the MFP  201  to transmit information concerning the erasing temperature of the toner  34  that forms the image to be erased. In Act  13 , the main CPU  63   a  waits for a response from the MFP  201 . 
     If the information concerning the erasing temperature is received from the MFP  201  (YES in Act  13 ), in Act  14 , the main CPU  63   a  controls the temperature of the erasing section  62  on the basis of the received information concerning the erasing temperature and erases the image. In Act  15 , the erasing section  62  discharges the erased sheet. 
     On the other hand, if no response is received even if a fixed time elapses after the request for the erasing temperature to the MFP  201  (NO in Act  13 ), in Act  16 , the main CPU  63   a  controls the erasing operation by the erasing section  62  at erasing temperature determined in advance. In Act  15 , the erasing section  62  discharges the erased sheet. 
     No response is received even if the fixed time elapses, for example, if the storage medium  33  is absent in the toner  34  during the detection (in Act  02  in  FIG. 6 ), if it is determined that the storage medium  33  is in a state equivalent to the absence of data, or if a communication state between the MFP  201  and the erasing device  60  is bad. 
     If the erasing temperature is controlled to the temperature determined in advance, naturally, it is not guaranteed that the erasing operation is performed at temperature optimum for the toner  34 . Therefore, since erasing could not be sufficiently performed depending on a case, if an image is printed using an erased sheet, visibility of the printed image is sometimes deteriorated. 
     If the information concerning the erasing temperature of the toner  34  is periodically transmitted from the MFP  201  to the erasing device  60  as explained above, the erasing device  60  can obtain an optimum erased image by controlling the temperature of the erasing section  62  on the basis of latest erasing temperature information. 
     Second Embodiment 
     A cooperated operation concerning erasing by the MFP  201  and the erasing device  60  according to a second embodiment is explained. The second embodiment is different from the first embodiment in that information concerning erasing temperature is printed on a sheet. Components same as or similar to those in the first embodiment are denoted by the same reference numerals and signs and explanation of details of the components is omitted. 
     In the first embodiment, the operation for erasing in a short period is explained. However, in the second embodiment, a method applicable even if a period until erasing is long is explained. 
       FIG. 8  is an exemplary flowchart for explaining an operation procedure concerning erasing by the MFP  201  according to the second embodiment. 
     When the operation start button for the MFP  201  is operated on the operation panel  9 , in Act  21 , the main control section  4  detects that the consumable for erasing (the toner)  34  is present. In Act  22 , the printer CPU  1   a  detects whether the storage medium  33  is present in the predetermined position of the toner  34 . 
     If the printer CPU  1   a  detects that the storage medium  33  is present (YES in Act  22 ), the printer CPU  1   a  reads information concerning erasing of the toner  34  stored in the storage medium  33 . The information concerning erasing includes erasing temperature, fixing temperature, and the like of the erasable toner. 
     In Act  23 , the printer CPU  1   a  reads the information concerning the erasing temperature of the erasable toner. In Act  24 , the main CPU  4   a  forms, in an image, the read information concerning the erasing temperature of the erasable toner and stores the read information in the storage device  4   b.    
       FIG. 10  is an exemplary diagram of a form of the information formed in the image by the MFP  201  according to the second embodiment. 
     The information concerning the erasing temperature of the erasable toner  34  is formed in a non-image region  70  of a sheet. The non-image region  70  is a region excluding a region  71  set for printing an image in a region of the entire sheet. 
     In the non-image region  70  of the sheet, the information concerning the erasing, temperature of the erasable toner  34  is formed as a pattern. In  FIG. 10 , a barcode is shown as an example of the pattern. However, the pattern may be a QR code or a pattern having a shape similar to the barcode or the QR code. The information to be formed may be a row of characters or numbers which is seemingly meaningless. However, the pattern such as the barcode or the QR code is desirable to prevent the pattern from being confused with a print file name. 
     On the other hand, in Act  25  in  FIG. 8 , the printer CPU  1   a  reads the information concerning the fixing temperature of the erasable toner  34 . In Act  26 , the printer CPU  1   a  controls the fixing temperature of the toner  34  on the basis of the read information concerning the fixing temperature and obtains an image in an optimum fixed state. In Act  28 , the fixing device  18  discharges a sheet on which the image is printed. 
     If the printer CPU  1   a  detects that the storage medium  33  is absent (NO in Act  22 ), in Act  27 , the printer CPU  1   a  controls the fixing temperature to temperature determined in advance. In Act  28 , the fixing device  18  discharges a sheet on which an image is printed. 
     The image formed on the sheet using the erasable toner is erased by the erasing device  60  after the image finishes a desired role. 
       FIG. 9  is an exemplary flowchart for explaining an operation procedure concerning erasing by the erasing device  60  according to the second embodiment. 
     When an erasing operation for an image to be erased is started, in Act  31 , the main CPU  63   a  starts reception of a sheet on which the image to be erased is printed. In Act  32 , the main CPU  63   a  reads, via the reading section  61 , the pattern formed in the non-image region  70  and acquires information concerning the erasing temperature. 
     The sheet is not always read by the erasing device  60  in the same direction as a direction in which the sheet is printed. Therefore, the main CPU  63   a  needs to execute processing for extracting the pattern after applying rotation or the like to image data read by the reading section  61 . 
     Even if the non-image region  70  is stained, in order to enable reading of the pattern, when the pattern is printed in the non-image region  70 , the erasable toner  34  of a specific color can be used. For example, in the case of an erasable toner including a cyan color material, the wavelength of the printed pattern is 450 to 500 nm. Therefore, it is possible to reduce noise by extracting the pattern from the non-image region  70  using an optical filter (e.g., a band-pass filter that transmits light having the wavelength 450 to 500 nm). 
     If the information concerning the erasing temperature is acquired from the sheet (YES in Act  33 ), in Act  34 , the main CPU  63   a  controls the temperature of the erasing section  62  on the basis of the acquired information concerning the erasing temperature and erases the image. In Act  35 , the erasing section  62  discharges the erased sheet. 
     On the other hand, if the information concerning the erasing temperature is not acquired from the sheet (NO in Act  33 ), in Act  36 , the main CPU  63   a  controls an erasing operation by the erasing section  62  at erasing temperature determined in advance. In Act  35 , the erasing section  62  discharges the erased sheet. 
     Third Embodiment 
     A cooperated operation concerning erasing by the NFP  201  and the erasing device  60  according to a third embodiment is explained. The third embodiment is different from the second embodiment in that information concerning erasing temperature is printed on a sheet and communication means is used according to necessity. Components same as or similar to those in the second embodiment are denoted by the same reference numerals and signs and explanation of details of the components is omitted. 
       FIG. 11  is an exemplary flowchart for explaining an operation procedure concerning erasing by the MFP  201  according to the third embodiment. 
     A processing procedure in the third embodiment shown in  FIG. 11  is the same as the processing procedure in the second embodiment shown in  FIG. 8  except that, in Act  49 , the MFP  201  transmits read information concerning erasing temperature in response to a request from the erasing device  60 . 
       FIG. 12  is an exemplary flowchart for explaining an operation procedure concerning erasing by the erasing device  60  according to the third embodiment. 
     Actions in Acts  51  to  55  shown in  FIG. 12  are the same as the actions in Acts  31  to  35  in the second embodiment shown in  FIG. 9 . 
     If the information concerning the erasing temperature is not acquired from the sheet (NO in Act  53 ), in Act  56 , the main CPU  63   a  requests, via the communication control CPU  64   a , the MFP  201  to transmit information concerning the erasing temperature of the toner  34  that forms the image to be erased. In Act  57 , the main CPU  63   a  waits for a response from the MFP  201 . 
     If the information concerning the erasing temperature is received from the MFP  201  (YES in Act  57 ), in Act  54 , the main CPU  63   a  controls the temperature of the erasing section  62  on the basis of the received information concerning the erasing temperature and erases the image. In Act  55 , the erasing section  62  discharges the erased sheet. 
     On the other hand, if the information concerning the erasing temperatures is not received from the MFP  201  (NO in Act  57 ), in Act  58 , the main CPU  63   a  controls the erasing operation by the erasing section  62  at erasing temperature determined in advance. In Act  55 , the erasing section  62  discharges the erased sheet. 
     Modification of the First to Third Embodiments 
     A cooperated operation concerning erasing by the MFP  201  and the erasing device  60  according to a modification of the first to third embodiments is explained on the basis of the second embodiment. In the modification, information concerning erasing temperature printed on a sheet is different from that in the second embodiment. 
     In Act  24  in  FIG. 8 , the main CPU  4   a  forms the read information concerning the erasing temperature of the erasable toner in a non-image region and stores the information in the storage device  4   b . Further, the main CPU  4   a  forms, in an image, data of the present date and time. 
     In Act  34  in  FIG. 9 , if date and time in the printed image is further in the past than the present by predetermined time, the erasing device  60  sets temperature in the fixing device  18  higher than the erasing temperature by predetermined temperature (a). Consequently, even on a sheet used when a long time elapses after printing with the erasable toner, it is possible to prevent occurrence of unevenness due to the toner remaining without being erased. 
     By adopting the configuration explained above, it is possible to obtain an image in which both of stable fixing characteristics and erasing characteristics are realized. 
     In the embodiments, the MFP  201  and the erasing device  60  are configured to be separated from each other. However, the MFP  201  and the erasing device  60  may be configured to be integrated. For example, the erasing device  60  may be incorporated in the MFP  201  or the fixing device  18  may be configured to be capable of functioning as an erasing device. 
     In the embodiments, the image forming apparatus of the electrophotographic system is explained. However, the present invention can also be applied to an image forming apparatus of an inkjet system. When the present invention is applied to the image forming apparatus of the inkjet system, liquid ink or gel ink is used rather than a toner. Fixing temperature can be grasped as heating temperature. 
     The functions explained in the embodiments may be configured using hardware. The functions may be realized by causing a computer to read a computer program that describes the functions using software. The functions may be configured by selecting the software or the hardware as appropriate. 
     Further, the functions can also be realized by causing the computer to read the computer program stored in a not-shown recording medium. A recording form of the recording medium in the embodiments may be any form as long as the recording medium can record the computer program and can be read by the computer. 
     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 inventions. 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 inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.