Abstract:
What is disclosed is an image forming apparatus which receives a job of a printing from outside of the apparatus with an instruction of changing a condition of transfer that corresponds to said job and that is valid only for said job. And, the image forming apparatus comprising: a transferring unit for transferring an image formed with a toner based on said job, a memory section for memorizing, and a setting section for setting a condition of transfer.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to an image forming apparatus which corrects a condition of transfer and an image forming system which includes this image forming apparatus.  
         [0003]     2. Description of Related Art  
         [0004]     In a process of printing performed by an ordinary image forming apparatus such as an apparatus with an electrophotographic method, first of all, a surface of a holder of an image is uniformly charged. On this surface of a holder of an image, a prescribed electrostatic latent image is formed by exposing the surface to a light. The electrostatic latent image is developed by a toner. Then, an image is formed with toner on the surface of a holder of the image. This image of toner is transferred, based on a control of levelling voltage or levelling current, on a recording medium by a transferring unit. A feature of the transfer is much influenced by a change of temperature or humidity of circumstances. To decrease this influence as low as possible, a method for controlling transfer is disclosed. This method is a method for transferring with a condition. This condition is set based on a resistance of the transferring unit. This resistance is calculated from a current detected and a voltage generated, when a prescribed current is flown in the transferring unit (c.f. JP2001-83751). Moreover, another method for controlling transfer is disclosed. This method is a method for transferring with a condition. This condition is set based on a data obtained from thirmal sensor (c.f. JP11-305565).  
         [0005]     Even in case that the two methods mentioned above are used, all the users cannot always obtain the best result of printing which they want.  
         [0006]     In case that either of the two methods mentioned above are used, each user can obtain near to the best result of printing which he or she wants. However, following inconvenience occurs. It occurs when an image forming apparatus is connected to a network and the image forming apparatus is commonly used by many users. When one of the many users changed the condition of transfer according to his own choice, other users do not like the changed condition. Then, another user obtains a result of printing which he does not want.  
         [0007]     That is, there is a problem to solve, that either of the other users obtain a result of printing which he does not want, when an image forming apparatus is connected to a network and the image forming apparatus is commonly used by many users, in case that one of the many users changed the condition of transfer according to his own choice and other users do not like the changed condition.  
       SUMMARY OF THE INVENTION  
       [0008]     According to one aspect of the present invention, there is provided an image forming apparatus which receives a job of a printing from outside of the apparatus with an instruction of changing a condition of transfer that corresponds to said job and that is valid only for said job.  
         [0009]     According to another aspect of the present invention, there is provided an image forming system where an image forming apparatus connected to the system receives a job of a printing from other apparatus connected to the system with an instruction of changing a condition of transfer that corresponds to said job and that is valid only for said job. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a block diagram showing an image forming system of the present invention;  
         [0011]      FIG. 2  is a sectional diagram showing a chief portion of electrophotographic process portion;  
         [0012]      FIG. 3  shows a setting table of standard information of transfer of Embodiment 1;  
         [0013]      FIG. 4  shows a setting table of standard information of transfer with limits of Embodiment 1;  
         [0014]      FIG. 5  is a flow chart showing an operation of Embodiment 1;  
         [0015]      FIG. 6  shows a property of an input unit of Embodiment 1;  
         [0016]      FIG. 7  shows another property of the input unit of Embodiment 1;  
         [0017]      FIG. 8  shows a setting table of standard information of transfer of Embodiment 2;  
         [0018]      FIG. 9  shows a setting table of standard information of transfer with limits of Embodiment 2;  
         [0019]      FIG. 10  shows a property of an input unit of Embodiment 2;  
         [0020]      FIG. 11  is a flow chart showing an operation of Embodiment 2. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     Embodiment 1  
       [0000]     Configuration  
         [0021]      FIG. 1  is a block diagram showing an image forming system of the present invention.  
         [0022]     As shown in  FIG. 1 , an image forming system  1  of Embodiment 1 comprising an information processing apparatus  2  and an image forming apparatus  3 . Here, the information processing apparatus  2  and the image forming apparatus  3  are connected with a serial interface or network not shown in the drawing.  
         [0023]     Before describing each structure of each apparatus in detail, a general structure of a mechanism of the image forming apparatus  3  will be described. As an example, chief component parts and an operation of an electrophotographic processing section will be described.  
         [0024]      FIG. 2  is a sectional diagram showing a chief portion of electrophotographic process portion.  
         [0025]     As shown in  FIG. 2 , an electrophotographic processing section  100  comprises a photosensitive drum  101 , a charging roller  102 , an LED array head  103 , a developing unit  104 , a transferring roller  105 , a fixing unit  106 , a cleaning roller  107  and a conveying belt  108 . A surface of the photosensitive drum  101  is uniformly charged by the charging roller  102 , when they rotate. When a charged portion of the photosensitive drum  101  reached to the LED array head  103  after the photosensitive drum  101  rotated, a ray of light is radiated by the LED array head  103 . And, a latent image of static electricity is formed on the surface of the photosensitive drum  101 .  
         [0026]     When the latent image of static electricity reached to the developing unit  104  after the photosensitive drum  101  rotated, the latent image of static electricity is developed by a toner supplied to the surface of a developing roller  104 A by a supplying roller  104 B. This developed image with a toner is transferred onto a recording medium conveyed on the conveying belt  108  moved by a transferring roller  105 . The present invention especially concerns to this section.  
         [0027]     This transferred image of a toner is fixed on a recording medium with a heat by a heating roller  106 A of a fixing unit  106  and with a pressure by a back up roller  106 B of the fixing unit  106 . On the other hand, a toner remained on the photosensitive drum  101  is cleaned by a cleaning roller  107 . That is all of the description of the general structure and operation of electrophotographic processing section.  
         [0028]     Therefore, returning to  FIG. 1 , the structure of the image forming system of the present invention will be described. For the convenience of describing the system, the image forming apparatus  3  will be described first. After that, the information processing apparatus  2  of a host device will be described next.  
         [0029]     The image forming apparatus  3  comprises a communication section  5 , a standard transferring parameter memory section  8 , a transfer limit memory section  9 , a correct transferring parameter memory section  10 , a transferring section  11  and an image holding body  21 . The communication section  5  is a section for connecting the image forming apparatus  3  with a serial interface or network not shown in the drawing, which is connected with the information processing apparatus  2 .  
         [0030]     The standard transferring parameter memory section  8  is a memory section for containing the standard information of transfer for each recording medium, to become a setting table contained beforehand. An example of the standard information of transfer, in case of control of levelling a voltage, is described as follows.  
         [0031]      FIG. 3  shows a setting table of standard information of transfer of Embodiment 1.  
         [0032]     As shown in  FIG. 3 , a setting table of standard information of transfer are contained corresponding to each kind of the recording media such as an ordinary sheet, a post card, an envelope etc. An abscissa of each table represents a value of resistance of the transferring unit. An ordinate of each table represents a voltage of transfer corresponding to each value of resistance of the transferring unit.  
         [0033]     The transfer limit memory section  9  contains a range where a correction is allowable, corresponding to each standard information of transfer. Why a range is set is as follows. Lack of transfer such as dim of an image occurs in case that the voltage of transfer is too low. Excess of transfer such as stain of an image occurs in case that the voltage of transfer is too high. Moreover, in case that the voltage of transfer is too high, an electric shock to an image holding body  21  occurs. These problems are solved by setting a range to the voltage of transfer. That is, a lower limit of the voltage and an upper limit of the voltage are contained in the transfer limit memory section  9 . Here, a lower limit of the voltage is a boundary to a region where lack of transfer occurs. And, an upper limit of the voltage is a boundary to a region where excess of transfer occurs.  
         [0034]      FIG. 4  shows a setting table of standard information of transfer with limits of Embodiment 1.  
         [0035]     As shown in  FIG. 4 , lower limit of the voltage and upper limit of the voltage are contained, adding to the setting table of standard information of transfer corresponding to each kind of the recording media such as an ordinary sheet, a post card, an envelope etc. So, a range between the lower limit of the voltage and the upper limit of the voltage, is a range where transfer is good.  
         [0036]     A correct transferring parameter memory section  10  is a memory section to memorize information of transfer for correction. Here, this information of transfer for correction is used for correcting the standard information of transfer according to a method of each user.  
         [0037]     This information of transfer for correction is selected from between the lower limit and the upper limit. That is, any user is not allowed to correct using a voltage selected from outside of the range between the lower limit and the upper limit.  
         [0038]     A transferring section  11  is a section for transferring an image formed with a toner, from the image holding body  21  to a recording medium  22 . This section comprises a transfer condition setting section  12 , a transferring control section  13 , a transferring unit  14  and a detecting section  15 .  
         [0039]     The transfer condition setting section  12  is a section for setting a condition of transfer according to standard information of transfer, and information of transfer for correction included in a printing job sent from the information processing apparatus  2 . That is, this is a section for deciding a condition of transfer to a value between the lower limit and the upper limit by using the standard information of transfer and the information of transfer for correction.  
         [0040]     The transferring control section  13  is a section for selecting a method of control of transfer. This transferring control section  13  comprises a constant voltage control section  16 , a constant current control section  17 , and a control changing section  18 . The constant voltage control section  16  is a section for performing a control of transfer with a method of controlling constant voltage. The constant current control section  17  is a section for performing a control of transfer with a method of controlling constant current. And, the control changing section  18  is a section for changing a control of transfer between the constant voltage control section  16  and the constant current control section  17 .  
         [0041]     The detecting section  15  is a sensor for detecting a value of a voltage impressed to the transferring unit  14  and a value of a current flown to the transferring unit  14 . The transferring unit  14  is a transferring roller  105  ( FIG. 2 ) for transferring an image formed with a toner on an image holding body  21  to a recording medium  22 , by impressing a strong electric field. The image holding body  21  is a section, that is, a photosensitive drum for forming an image with a toner on a latent image of static electricity on a surface of a drum based on a bit map data received from the information processing apparatus  2 .  
         [0042]     That is all of the description of the image forming apparatus  3 . Subsequently, a description about the information processing apparatus  2  will be performed.  
         [0043]     When a user inputs information of an image to request printing (forming an image), the information processing apparatus  2  generates a prescribed printing job and send it out to the image forming apparatus  3 . Thus, the information processing apparatus  2  corresponds to an outer apparatus set forth in the claims. It comprises a communication section  4 , driver  6  and an input section  7 .  
         [0044]     The communication section  4  is a section for operating as an interface which connects the information processing apparatus  2  with a serial interface or network not shown in the drawing, connected with the image forming apparatus  3 . The driver  6  is a section for sending information of an image inputted by a user, to the communication section  4 , after changing the information of an image to a printing job.  
         [0045]     The input section  7  is a section for functioning as an interface between the information processing apparatus  2  and the user in order to input information of an image requested by the user. Especially in the present invention, the information processing apparatus  2  is a section for inputting information for selection, selecting specific standard information of transfer, among plural standard information of transfer, which are memorized in the standard transferring parameter memory section  8 ; and information of transfer for correction, for correcting the specific standard information of transfer according to a method of the user.  
         [0046]     That is all of the description about the image forming system of the present invention. Subsequently, an operation of the image forming system of the present invention will be described.  
         [0000]     Operation  
         [0000]    
       
         
           
               FIG. 5  is a flow chart showing an operation of Embodiment 1.  
               FIG. 6  shows a property of an input unit of Embodiment 1.  
               FIG. 7  shows another property of the input unit of Embodiment 1.  
           
         
       
     
         [0050]     Referring to steps S 101  to S 116  of  FIG. 5 , an operation of the image forming system of Embodiment 1 will be described in order of these steps.  
         [0051]     STEP S 101   
         [0052]     First of all, a user is requested to input a characteristic of the recording media, so as to decide a standard information of transfer for the recording media which need correction. At this time, a property for input of media characteristic  601  shown in  FIG. 6  is presented at an presenting apparatus (not shown in the drawings) of an input section  7  (c.f.  FIG. 1 ). By using this property, the user select a size of media  602  (ordinary sheets or narrow sheets), a thickness of media  603  (ordinary sheets, thin sheets or thick sheets), a kind of media  604  (ordinary sheets, post cards, envelopes or OHP sheets). That is, each selection is inputted.  
         [0053]     STEP S 102   
         [0054]     After the standard information of transfer is decided, succeedingly, a property for input of correcting transfer  605  shown in  FIG. 6  is presented at an presenting apparatus of an input section  7  not shown in  FIG. 6 . A present correcting value  606  corresponding to the standard information of transfer, is presented.  
         [0055]     STEP S 103   
         [0056]     The user inputs a correcting value according to the above property. For example, proportion of a value  607  for correction of transfer based on the standard information of transfer, is inputted. A method of inputting, is to put a desired numerical value directly to an input area with a keyboard etc. or to adjust a presented numerical value to a desired value with operating a pair of up-down buttons to increase the value or to decrease the value.  
         [0057]     STEP S 104   
         [0058]     A selection to select the standard information for the recording media, and the information of correction for the standard information mentioned above; are included in a printing job with data for printing. And, this printing job is sent from the information processing apparatus  2  to the image forming apparatus  3  through the communication section  4  and  5 . In the image forming apparatus  3 , a specific data of the standard information is selected by the selection included in the printing job, from plural data of the standard information contained in the standard transferring parameter memory section  8 . Moreover, a data of the information of correction is memorized in the transfer correction memory section  10 . The transfer condition setting section  12  adds the value for correction to the value of the standard information selected. At the same time, it reads out a limit value corresponding to the standard information selected, from the transfer limit memory section  9 .  
         [0059]     STEP S 115   
         [0060]     The transfer condition setting section  12  compares a value obtained by adding the correction value to the standard value, with a lower limit value of transfer. In case that the added value is larger than the lower limit value, the process proceeds to STEP S 106 . In case that the added value is smaller than the lower limit value, the process proceeds to STEP S 108 .  
         [0061]     STEP S 106   
         [0062]     The transfer condition setting section  12  compares the added value mentioned above, with an upper limit value of transfer. In case that the added value is smaller than the upper limit value, the process proceeds to STEP S 107 . In case that the added value is larger than the upper limit value, the process proceeds to STEP S 109 .  
         [0063]     STEP S 107   
         [0064]     The transfer condition setting section  12  sets a value for the condition of transfer, to the standard value plus the correction value.  
         [0065]     STEP S 108   
         [0066]     The transfer condition setting section  12  sets a value for the condition of transfer, to the lower limit of transfer.  
         [0067]     STEP S 109   
         [0068]     The transfer condition setting section  12  sets a value for the condition of transfer, to the upper limit of transfer.  
         [0069]     STEP S 110   
         [0070]     The transferring control section  13  accept the value set by the transfer condition setting section  12 . Then, a transferring unit  14  is impressed with a corresponding voltage for transfer, so as to start printing.  
         [0071]     STEP S 111   
         [0072]     After starting of printing, a detecting section  15  starts measuring a voltage for transfer and a current for transfer. The transfer condition setting section  12  compares the measured value obtained by the detecting section  15 , with a lower limit value of transfer. In case that the measured value is larger than the lower limit value, the process proceeds to STEP S 112 . In case that the measured value is smaller than the lower limit value, the process proceeds to STEP S 114 .  
         [0073]     STEP S 112   
         [0074]     The transfer condition setting section  12  compares the measured value obtained by the detecting section  15 , with an upper limit value of transfer. In case that the measured value is smaller than the upper limit value, the process proceeds to STEP S 113 . In case that the measured value is larger than the upper limit value, the process proceeds to STEP S 115 .  
         [0075]     STEP S 113   
         [0076]     The transfer condition setting section  12  keeps a value for the condition of transfer, to the standard value plus the correction value.  
         [0077]     STEP S 114   
         [0078]     The transfer condition setting section  12  changes to set a value for the condition of transfer, to the lower limit of transfer.  
         [0079]     STEP S 115   
         [0080]     The transfer condition setting section  12  changes to set a value for the condition of transfer, to the upper limit of transfer.  
         [0081]     STEP S 116   
         [0082]     The above STEP&#39;s S 111  to S 116  are repeated until printing for all the printing data is finished. When printing for all the printing data is finished, the process ends.  
         [0000]     Effects  
         [0083]     As described above, according to Embodiment 1, when the user inputted a value for correcting transfer based on the user&#39;s own method with using an input device provided at an information processing apparatus, the information processing apparatus sends the information for correcting transfer included in a printing job, to an image forming apparatus. The information for correcting transfer, is used only for the job that includes the information. Therefore, each user never worry that the transfer be changed by other users. Each user always gets the user&#39;s own transfer. Moreover, a user never worry that each printing job be printed with a wrong transfer. Each printing job is always performed with a suitable transfer, because each printing job gets the job&#39;s own transfer. That is, when a change for transfer becomes needless, the user does not need to recover the former transfer, unlike the conventional printer or printing system.  
         [0084]     Incidentally, in the above description, a property shown in  FIG. 6  is described. However, the present invention is not limited to this example. That is, another property shown in  FIG. 7  can be adopted. In this property, selection for the standard information and an inputting operation for correcting the standard information, can be performed at a same time. That is, STEP S 102  and S 103  of  FIG. 5  are combined to perform a STEP.  
       Embodiment 2  
       [0000]     Configuration  
         [0085]     In Embodiment 1, a condition of transfer is set regardless of circumstance such as temperature or humidity. However, an adequate condition of transfer can change according to the circumstance. Therefore, in Embodiment 2, provided is an apparatus or system that can correct the condition of transfer according to a specific circumstance.  
         [0086]     Hereafter, only different points from Embodiment 1 will be described.  
         [0087]      FIG. 8  shows a setting table of standard information of transfer of Embodiment 2.  
         [0088]     As shown in  FIG. 8 , a setting table of standard information of transfer are contained corresponding to each kind of the recording media such as an ordinary sheet, a post card, an envelope etc. An abscissa of each table represents a value of resistance of the transferring unit. An ordinate of each table represents a voltage of transfer corresponding to each value of resistance of the transferring unit. Further, the setting table is divided into three regions of a low resistance (high temperature and high humidity), a middle resistance (ordinary temperature and ordinary humidity) and a high resistance (low temperature and low humidity).  
         [0089]      FIG. 9  shows a setting table of standard information of transfer with limits of Embodiment 2.  
         [0090]     As shown in  FIG. 9 , lower limit of the voltage and upper limit of the voltage are contained, adding to the setting table of standard information of transfer corresponding to each kind of the recording media such as an ordinary sheet, a post card, an envelope etc. So, a range between the lower limit of the voltage and the upper limit of the voltage, is a range where transfer is good. Further, the setting table is divided into three regions of a low resistance (high temperature and high humidity), a middle resistance (ordinary temperature and ordinary humidity) and a high resistance (low temperature and low humidity).  
         [0091]      FIG. 10  shows a property of an input unit of Embodiment 2.  
         [0092]     As shown in  FIG. 10 , a property of an inputting unit of Embodiment 2, is what is added to a property of an inputting unit of Embodiment 1 a selection of circumstance. In Embodiment 2, coping with a specific circumstance, the same effect as Embodiment 1 is obtained.  
         [0093]     The other component parts are same as Embodiment 1. So, the description is omitted. Subsequently, an operation of Embodiment 2 will be described.  
         [0000]     Operation  
         [0094]      FIG. 11  is a flow chart showing an operation of Embodiment 2.  
         [0095]     STEP S 201   
         [0096]     First of all, a user is requested to input a characteristic of the recording media, so as to decide a standard information of transfer for the recording media which need correction. At this time, a property for input of media characteristic  601  shown in  FIG. 10  is presented at an presenting apparatus (not shown in the drawings) of an input section  7  (c.f.  FIG. 1 ). By using this property, the user select a size of media  602  (ordinary sheets or narrow sheets), a thickness of media  603  (ordinary sheets, thin sheets or thick sheets), a kind of media  604  (ordinary sheets, post cards, envelopes or OHP sheets), and a circumstance  608  (low temperature and low humidity, ordinary temperature and ordinary humidity, and high temperature and high humidity). That is, each selection including circumstance is inputted.  
         [0097]     STEP S 202   
         [0098]     After the standard information of transfer is decided, succeedingly, a property for input of correcting transfer  605  shown in  FIG. 10  is presented at a presenting apparatus of an input section  7  not shown in  FIG. 10 . A present correcting value  606  corresponding to the standard information of transfer, is presented.  
         [0099]     STEP S 203   
         [0100]     The user inputs a correcting value according to the above property. For example, proportion of a value  607  for correction of transfer based on the standard information of transfer, is inputted. A method of inputting, is to put a desired numerical value directly to an input area with a keyboard etc. or to adjust a presented numerical value to a desired value with operating a pair of up-down buttons to increase the value or to decrease the value.  
         [0101]     STEP S 204   
         [0102]     A selection to select the standard information for the recording media, the information of circumstance and the information of correction for the standard information mentioned above; are included in a printing job with data for printing. And, this printing job is sent from the information processing apparatus  2  to the image forming apparatus  3  through the communication section  4  and  5 . In the image forming apparatus  3 , a thermal sensor and a humid sensor for circumstance not shown in the drawings are provided, so as to send results of detection to the transfer condition setting section  12 . The transfer condition setting section  12  judges from the results of detection, which region the present circumstance belongs to, among “low temperature and low humidity”, “ordinary temperature and ordinary humidity”, and “high temperature and high humidity”.  
         [0103]     A selection to select the standard information for the recording media, the information of circumstance and the information of correction for the standard information mentioned above; included in a printing job with data for printing; are sent to the image forming apparatus  3 . In the image forming apparatus  3 , a specific data of the standard information is selected by the selection included in the printing job, from plural data of the standard information contained in the standard transferring parameter memory section  8 . Moreover, a data of the information of correction is memorized in the transfer correction memory section  10 .  
         [0104]     STEP S 205   
         [0105]     The transfer condition setting section  12  judges whether the information of circumstance inputted at STEP S 201  accords with the information of circumstance detected at STEP S 204 . In case that the information of circumstance does not accord, the process proceeds to STEP S 206 . In case that the information of circumstance accords, the process proceeds to STEP S 209 .  
         [0106]     STEP S 206   
         [0107]     The transfer condition setting section  12  does not perform, because it cannot get information for correcting transfer. Therefore, the transfer condition setting section  12  sets the condition of transfer, to standard information of transfer.  
         [0108]     STEP S 207   
         [0109]     The transferring control section  13  accept the value set by the transfer condition setting section  12 . Then, a transferring unit  14  is impressed with a corresponding voltage for transfer, so as to start printing.  
         [0110]     STEP S 208   
         [0111]     When printing for all the printing data is finished, the process ends.  
         [0112]     STEP S 209   
         [0113]     The transfer condition setting section  12  adds the value for correction to the value of the standard information selected. At the same time, it reads out a limit value corresponding to the standard information selected, from the transfer limit memory section  9 .  
         [0114]     STEP S 210   
         [0115]     The transfer condition setting section  12  compares a value obtained by adding the correction value to the standard value, with a lower limit value of transfer. In case that the added value is larger than the lower limit value, the process proceeds to STEP S 211 . In case that the added value is smaller than the lower limit value, the process proceeds to STEP S 213 .  
         [0116]     STEP S 211   
         [0117]     The transfer condition setting section  12  compares the added value mentioned above, with an upper limit value of transfer. In case that the added value is smaller than the upper limit value, the process proceeds to STEP S 212 . In case that the added value is larger than the upper limit value, the process proceeds to STEP S 214 .  
         [0118]     STEP S 212   
         [0119]     The transfer condition setting section  12  sets a value for the condition of transfer, to the standard value plus the correction value.  
         [0120]     STEP S 213   
         [0121]     The transfer condition setting section  12  sets a value for the condition of transfer, to the lower limit of transfer.  
         [0122]     STEP S 214   
         [0123]     The transfer condition setting section  12  sets a value for the condition of transfer, to the upper limit of transfer.  
         [0124]     STEP S 215   
         [0125]     The transferring control section  13  accept the value set by the transfer condition setting section  12 . Then, a transferring unit  14  is impressed with a corresponding voltage for transfer, so as to start printing.  
         [0126]     STEP S 216   
         [0127]     After starting of printing, a detecting section  15  starts measuring a voltage for transfer and a current for transfer. The transfer condition setting section  12  compares the measured value obtained by the detecting section  15 , with a lower limit value of transfer. In case that the measured value is larger than the lower limit value, the process proceeds to STEP S 217 . In case that the measured value is smaller than the lower limit value, the process proceeds to STEP S 219 .  
         [0128]     STEP S 217   
         [0129]     The transfer condition setting section  12  compares the measured value obtained by the detecting section  15 , with an upper limit value of transfer. In case that the measured value is smaller than the upper limit value, the process proceeds to STEP S 218 . In case that the measured value is larger than the upper limit value, the process proceeds to STEP S 220 .  
         [0130]     STEP S 218   
         [0131]     The transfer condition setting section  12  keeps a value for the condition of transfer, to the standard value plus the correction value.  
         [0132]     STEP S 219   
         [0133]     The transfer condition setting section  12  changes to set a value for the condition of transfer, to the lower limit of transfer.  
         [0134]     STEP S 220   
         [0135]     The transfer condition setting section  12  changes to set a value for the condition of transfer, to the upper limit of transfer.  
         [0136]     STEP S 221   
         [0137]     The above STEP&#39;s S 216  to S 221  are repeated until printing for all the printing data is finished. When printing for all the printing data is finished, the process ends.  
         [0000]     Effects  
         [0138]     As described above, according to Embodiment 2, when the user inputted a value for correcting transfer based on the user&#39;s own method and circumstance with using an input device provided at an information processing apparatus, the information processing apparatus sends the information for correcting transfer and circumstance included in a printing job, to an image forming apparatus. The information for correcting transfer and circumstance, is used only for the job that includes the information. Therefore, each user never worry that the transfer be changed by other users. Each user always gets the user&#39;s own transfer. Moreover, correction of transfer is performed under the consideration of circumstance.  
         [0139]     Incidentally, detection of circumstance is performed by sensors not shown in the drawings provided in the image forming apparatus. However, the present invention is not limited to this example. That is, circumstance can be detected from a value of resistance of the transferring unit  14 . Here, the resistance is calculated from a current and a voltage of the transferring unit  14 . So, a voltage generated at the transferring unit  14 ; when a prescribed current detected beforehand, flows in the transferring unit  14 ; is detected by the voltage detecting section  19 .  
         [0140]     In the description mentioned above, only an electrophotographic printer is described as an example of an image forming apparatus of the present invention. However, the present invention is not limited to this example. That is, the present invention is able to be applied to a copy machine or facsimile which gives the same effects mentioned above.