Patent Publication Number: US-8537382-B2

Title: Image forming apparatus that delays communication during an abnormal communication state of a data signal computer readable medium storing program and method for image forming

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2010-070173 filed Mar. 25, 2010. 
     BACKGROUND 
     Technical Field 
     The present invention relates to an image forming apparatus, a computer readable medium storing a program and a method for image forming. 
     SUMMARY 
     According to an aspect of the present invention, there is provided an image forming apparatus including: a monitor that monitors a state of communication performed in the image forming apparatus; and a controller that, when the monitor monitors that the state of the communication is abnormal, controls the communication based on an operation of the image forming apparatus in which a state has been changed within previously determined time including a time point at which the state of the communication has become abnormal. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An exemplary embodiment of the present invention will be described in detail based on the following figures, wherein: 
         FIG. 1  is a cross-sectional view of an image forming apparatus according to an exemplary embodiment of the present invention; 
         FIG. 2  is a schematic cross-sectional view showing an image forming unit in  FIG. 1  in more detail; 
         FIG. 3  is a block diagram showing a configuration of a communication control program which operates in an apparatus main body controller in  FIG. 1 ; 
         FIGS. 4A to 4C  are examples of data signals indicating communication states; 
         FIG. 5  illustrates an example of periods indicating rotational positions of a photoreceptor drum; 
         FIG. 6  is a timing chart for explaining the communication control program in  FIG. 3  in more detail; 
         FIG. 7  is a timing chart showing control of communication between the apparatus main body controller and an image forming unit controller; 
         FIG. 8  is a flowchart showing an operation (S 10 ) of the communication control program in  FIG. 3 ; and 
         FIG. 9  is a block diagram showing a configuration of a second communication control program which operates in the apparatus main body controller in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Hereinbelow, an exemplary embodiment of the present invention will be described in detail based on the drawings. 
     Note that the following description is merely an example of implementation of the present invention and the present invention is not limited to the example described below but may be arbitrarily changed in accordance with necessity. 
     For example, an image forming apparatus according to the exemplary embodiment of the present invention is described below as a color printer; however, the image forming apparatus may be another device than the color printer (for example, a monochrome printer, a facsimile machine or a multi-function device). Further, another device than the image forming apparatus (for example, a personal computer) may be used. 
       FIG. 1  is a cross-sectional view of an image forming apparatus according to the exemplary embodiment of the present invention. 
     As shown in  FIG. 1 , an image forming apparatus  1  according to the exemplary embodiment of the present invention has an apparatus main body  10  as well as an operation panel  20 , a scanner  30  and a paper feeder  40 , which are attached to the apparatus main body  10 . 
     Further, the apparatus main body  10  has image forming units  12 Y (Yellow),  12 M (Magenta),  12 C (Cyan) and  12 K (blacK) provided for colors forming a color image. 
     Note that in the following drawings, “n” does not always indicate the same number, and substantially the same components have the same reference numerals. 
     Note that hereinbelow, when any one of plural components such as “image forming units  12 Y,  12 M,  12 C and  12 K” is given without being specified, it may be simply abbreviated to e.g. an “image forming unit  12 ”. 
     Further, the apparatus main body  10 , the image forming unit  12  and the paper feeder  40 , respectively having a controller, operate under the control of the controller. 
     Note that although not shown, an apparatus main body controller  100  of the apparatus main body  10 , an image forming unit controller  120  of the image forming unit  12  and a paper feeder controller  400  of the paper feeder  40  are control circuit boards having a CPU, a memory, a storage medium, a bus connecting these elements, and the like. These control circuit boards are communicably interconnected via cables, connectors and the like. 
     The apparatus main body  10  has the image forming unit  12  to form a toner image, an intermediate transfer belt  102  on which the toner image is transferred from the image forming unit  12 , a transfer roller  104  to transfer the toner image to paper in a position opposite to the image forming unit  12 , a fixing part  106  to fix the toner image transferred to the paper, and a paper conveyance passage  110  to convey the paper. 
     The fixing part  106  is provided with a flash lamp  108 . The toner image is fixed with optical energy emitted from the flash lamp  108 . 
     The paper conveyance passage  110  is provided with plural pairs of conveyance rollers  112  along the paper conveyance passage  110 . In the paper conveyance passage  110 , the printed surface of the paper on which print processing has been performed is faced down and discharged to the discharge tray  114 . 
     The operation panel  20  receives a print processing command (for example to print-output image data) from a user, and transmits the received print processing command to the apparatus main body controller  100 . 
     Note that although not shown, the operation panel  20  is communicably connected to the apparatus main body controller  100  via a cable, a connector and the like. 
     The scanner  30  reads a set original, and transmits the read content as image data to the apparatus main body controller  100 . 
     Note that although not shown, the scanner  30  is communicably connected to the apparatus main body controller  100  via a cable, a connector and the like. 
     The paper feeder  40  has a paper feed tray  402 . The paper feed tray  402  is provided with a paper feed head  404 . Upon reception of the print processing command with the apparatus main body controller  100  as a trigger, the paper feed head  404  is actuated, and paper is supplied from the paper feed tray  402  via a paper feed passage  406  to the apparatus main body  10 . As in the case of the paper conveyance passage  110 , the paper feed passage  406  is provided with plural pairs of conveyance rollers  112  along the paper feed passage  406 . 
     Note that although not shown, a part of the side surface of the paper feeder  40  on the side of the apparatus main body  10  is utilized as a guide surface to communicate the paper feed passage  406  to the paper conveyance passage  110 . 
       FIG. 2  is a schematic cross-sectional view showing the image forming unit  12  in  FIG. 1  in more detail. 
     As shown in  FIG. 2 , the image forming unit  12  has a photoreceptor drum  122 , a charging device  124 , an exposure device  126 , a developing roller  128  and a pre-transfer charging unit  130 . 
     The photoreceptor drum  122  has a photo conductive layer such as an OPC (Organic Photo Conductor) on its surface. 
     The charging device  124  applies electric charge to the surface of the photoreceptor drum  122  to uniformly charge the surface of the charging device  124 . 
     The exposure device  126 , having a light beam emission source such as a laser diode, emits a light beam on the charged surface of the photoreceptor drum  122 , thereby eliminates charge in the irradiated part and forms an electrostatic latent image corresponding to an output image. 
     The developing roller  128  supplies toner corresponding to the output image to the photoreceptor drum  122 , thereby forms a toner image from the electrostatic latent image on the surface of the photoreceptor drum  122 . 
     The pre-transfer charging unit  130  applies electric charge to the surface of the photoreceptor drum  122 , thereby uniformly charges the surface of the photoreceptor drum  122  prior to transfer by the transfer roller  104 . 
       FIG. 3  is a block diagram showing a configuration of a communication control program  50  which operates in the apparatus main body controller  100  in  FIG. 1 . 
     The communication control program  50  is stored on the memory, the storage medium or the like, and read and executed by the CPU. 
     As shown in  FIG. 3 , the communication control program  50  has a monitor  500 , a memory  502 , an inquiry part  504 , a determination part  506  and a communication controller  508 . 
     The monitor  500  monitors states of communication between the apparatus main body controller  100  and the image forming unit controller  120 , the paper feeder controller  400 , the operation panel  20  and the scanner  30  connected to the apparatus main body controller  100 , and communication between the image forming unit controllers  120 . 
     The communication states are monitored as e.g. data signals shown in  FIGS. 4A to 4C . 
     When the data signal in  FIG. 4A  is monitored, the communication state is normal. 
     When the data signal in  FIG. 4B  is monitored, although noise is superimposed on the data signal, the noise can be eliminated by sampling or the like. Accordingly, the communication state is normal. 
     When the data signal in  FIG. 4C  is monitored, since noise which cannot be eliminated without difficulty is superimposed on the data signal, the communication state is abnormal. However, even when the data signal in  FIG. 4C  is monitored, there is a probability that a communication abnormality does not actually occur but an abnormality caused in the component of the image forming apparatus  1  influences the communication state. For example, failure of a motor which actuates the component of the image forming apparatus  1  increases load current, which causes serious induction noise upon starting of the motor, and the noise is superimposed on the data signal. 
     In the memory  502  in  FIG. 3 , based on the operation state of each of the components of the image forming apparatus  1 , a timing at which the communication state becomes abnormal (hereinbelow, “abnormal timing”) and the number of times of occurrence of an abnormality in the communication state (hereinbelow, “abnormal times”), linked with each other, are stored. 
     Note that the information stored in the memory  502  may be deleted upon power-on or power-off of the image forming apparatus  1 , or may be deleted based on an instruction inputted by the user with respect to the operation panel  20 . Further, the information may be deleted upon change of the component(s) of the image forming apparatus  1 . 
     Further, upon deletion of the information, all the abnormal times and abnormal timings may be deleted or only the abnormal times beyond a previously determined (hereinbelow, “predetermined”) threshold value and abnormal timings corresponding to these abnormal times may be deleted. 
     Upon monitoring of a communication state abnormality by the monitor  500  as a trigger, the inquiry part  504  inquires about the operation states of the respective components of the image forming apparatus  1 , and transmits the results of inquiry to the determination part  506 . The operation states of the respective components of the image forming apparatus  1  are indicated as e.g. ON/OFF data signals from the respective components of the image forming apparatus  1 . 
     Note that it may be arranged such that the inquiry part  504  inquires about the temperature and the humidity in the image forming apparatus  1  detected by sensors (not shown) in addition to the operation states of the respective components of the image forming apparatus  1 , or it may be arranged such that the inquiry part  504  inquires about a rotational position of the photoreceptor drum  122  in  FIG. 2 . The rotational position of the photoreceptor drum  122  is indicated as, e.g., a period divided from the period of 1 rotation of the photoreceptor drum  122  (here, divided period  1 , divided period  2 , . . . divided period N−1 and divided period N) as shown in  FIG. 5 . 
     The determination part  506  in  FIG. 3  determines an abnormal timing based on the operation state of each of the components of the image forming apparatus  1  obtained from the inquiry by the inquiry part  504 . 
     For example, in a component of the image forming apparatus  1 , when an abnormality in its communication state is monitored and the operation state is changed at the same time, the time point at which the operation state in the component has been changed is determined as an abnormal timing. 
     Further, the determination part  506  stores the determined abnormal timing in the memory  502  and counts up the abnormal times corresponding to the determined abnormal timing. 
     When the abnormal times counted by the determination part  506  exceeds a predetermined threshold value (that is, the abnormal times at the same abnormal timing exceeds the predetermined threshold value), the communication controller  508  controls a communication interface (not shown) provided in the apparatus main body controller  100 , the image forming unit controller  120 , the paper feeder controller  400 , the operation panel  20 , the scanner  30  and the like so as to control a communication timing. 
       FIG. 6  is a timing chart for explaining the communication control program  50  in  FIG. 3  in more detail. 
     As shown in  FIG. 6 , the respective components of the image forming apparatus  1  (here, the photoreceptor drum  122 , the developing roller  128 , the pre-transfer charging unit  130 , the transfer roller  104 , the charging device  124 , the exposure device  126  and the paper conveyance passage  110  shown in  FIG. 2 ) operate, and the image forming unit controllers  120 K and  120 C communicate with each other. 
     When the communication control program  50  is executed, and the monitor  500  in  FIG. 3  first monitors an abnormality in the communication between the image forming unit controllers  120  (( 1 ) in  FIG. 6 ), the inquiry part  504  in  FIG. 3  inquires about the operation states of the respective components of the image forming apparatus  1 . The determination part  506  in  FIG. 3  determines an abnormal timing, and stores the determined abnormal timing (here, timing of actuation of the transfer roller  104  as shown in ( 2 ) in  FIG. 6 ) and the abnormal times (here, once), linked with each other, into the memory  502  in  FIG. 3 . 
     Further, when the abnormal times in the communication between the image forming unit controllers  120  exceeds a predetermined number of times (e.g., five times), in the subsequent communication, the communication controller  508  in  FIG. 3  delays communication start time so as not to perform communication at the abnormal timing which influences communication state due to actuation of the transfer roller  104 . Note that it may be arranged such that the communication controller  508  reduces the number of times of communication so as not to perform communication at the abnormal timing. 
     More particularly, as shown in ( 3 ) in  FIG. 6 , control is performed so as to delay the communication start timing by time T 1 . It may be arranged such that the time T 1  is previously stored, linked with an abnormal timing, in the memory  502  or the like and read from the memory  502 , otherwise, it may be arranged such that the time T 1  is obtained by adjusting previously-stored time in correspondence with the temperature and the humidity in the image forming apparatus  1  and/or the rotational position of the photoreceptor drum  122 . 
     Time T 2  is previously set such that it is longer than time T 3  logically required for communication for a predetermined data amount (such that the time T 2  includes margin M). 
     Especially, when time T 4  obtained by subtracting the time T 1  from the time T 2  is shorter than the time T 3 , since a part of predetermined data cannot be communicated, the time T 1  is reduced such that the time T 4  is longer than the time T 3  or communication is also performed in the time T 1 . Note that communication may be performed sequentially from data with the highest priority in consideration of a probability that data with low priority cannot be communicated. 
     Further, it may be arranged such that, in the subsequent communication, when the accumulated time of the time T 1  exceeds a predetermined threshold value, a warning is displayed on the operation panel  20  or the like. 
     Further, it may be arranged such that, a warning is displayed on the operation panel  20  or the like only when the accumulated time of the time T 1  exceeds the predetermined threshold value in not all the communications but in predetermined communication (for example, only communication between the image forming unit controllers  120 ). 
     The above description has been made about communication between the image forming unit controllers  120  as an example, and further, communication between the apparatus main body controller  100  and the image forming unit controller  120  is similarly performed. 
     For example, as shown in  FIG. 7 , when an abnormal timing is a time point of light emission in the flash lamp  108  in  FIG. 1 , the apparatus main body controller  100  controls the timing of video data transmission not to transmit the video data to the image forming unit controller  120  during the time of light emission in the flash lamp  108 . 
       FIG. 8  is a flowchart showing the operation (S 10 ) of the communication control program  50  in  FIG. 3 . 
     As shown in  FIG. 8 , at step S 100 , it is determined whether or not an abnormality of communication state has been monitored by the monitor  500  in  FIG. 3 . When it is determined that the communication state has become abnormal, the process proceeds to step S 102 , otherwise, the determination is repeated until the communication state becomes abnormal. 
     At step S 102 , the inquiry part  504  in  FIG. 3  inquires about the operation states of the respective components of the image forming apparatus  1  in  FIG. 1 . Note that the inquiry part  504  may inquire about the temperature and the humidity in the image forming apparatus  1  and/or the rotational position of the photoreceptor drum  122  in  FIG. 2 , in addition to the operation states of the respective components of the image forming apparatus  1 . 
     At step S 104 , the determination part  506  in  FIG. 3  determines an abnormal timing based on the operation states of the respective components of the image forming apparatus  1  inquired at step S 102 . 
     At step S 106 , the determination part  506  stores the determined abnormal timing in the memory  502  in  FIG. 3 , and counts up the abnormal times corresponding to the determined abnormal timing. 
     At step S 108 , the determination part  506  determines whether or not the abnormal times counted up at step S 106  exceeds a predetermined threshold value. When it is determined that the abnormal times exceeds the predetermined threshold value, the process proceeds to step S 110 , otherwise, returns to step S 100 . 
     At step S 110 , the communication controller  508  in  FIG. 3  reads the time T 1  in which communication is not performed from the memory  502  or the like based on the abnormal timing determined at step S 104 . Note that it may be arranged such that the read time T 1  is adjusted in correspondence with the temperature and the humidity in the image forming apparatus  1  and/or the rotational position of the photoreceptor drum  122 . 
     At step S 112 , the communication controller  508  subtracts the time T 1  calculated at step S 110  from the previously-set time T 2  for a predetermined data amount, thereby calculates the time T 4 . 
     At step S 114 , the communication controller  508  determines whether or not the time T 4  calculated at step S 112  is shorter than the time T 3  required for communication for the predetermined data amount. When it is determined that the time T 4  is shorter the time T 3 , the process proceeds to step S 116 , otherwise, proceeds to step S 118 . 
     At step S 116 , the communication controller  508  adjusts the time T 1  calculated at step S 110  such that the time T 4  becomes longer than the time T 3 , or performs control to also perform communication in the time T 1 . 
     At step S 118 , the communication controller  508  delays the communication start timing by the time T 1  or does not delay the communication start timing, so as not to perform the communication during the time T 1  read at step S 110  (or the time T 1  adjusted at step S 116 ). 
     As described above, the states of communication between the apparatus main body controller  100 , and the image forming unit controller  120 , the paper feeder controller  400 , the operation panel  20 , and the scanner  30  connected to the apparatus main body controller  100 , and communication between the forming unit controllers  120  are monitored, and the communication is controlled based on a timing at which communication state becomes abnormal. 
     However, when noise of the power source is detected, in accordance with the degree of noise, there is a strong probability that the noise influences the communication state. 
     Accordingly, it may be arranged such that the power source of the image forming apparatus  1 , power sources of the components of the image forming apparatus  1 , the signal ground and the frame ground and the like are monitored, and communication is controlled based on a timing of detection of noise at a predetermined or higher level. 
     [Modification] 
       FIG. 9  is a block diagram showing a configuration of a second communication control program  60  which operates in the above case in the apparatus main body controller  100  in  FIG. 1 . 
     As shown in  FIG. 9 , the communication control program  60  has a monitor  600 , a memory  602 , the inquiry part  504 , a determination part  604  and the communication controller  508 . 
     The monitor  600  monitors the power source of the image forming apparatus  1 , the power sources of the components of the image forming apparatus  1 , the signal ground and the frame ground. 
     In the memory  602 , timings of noise detection (hereinbelow, “noise detection timing”) and the number of times of noise detection (hereinbelow, “noise detection times”), linked with each other, are stored based on the operation states of the respective components of the image forming apparatus  1 . 
     Upon monitoring of noise in the power source of the image forming apparatus  1 , the power sources of the components of the image forming apparatus  1 , the signal ground and the frame ground by the monitor  600  as a trigger, the inquiry part  504  inquires about the operation states of the respective components of the image forming apparatus  1  and transmits the obtained operation states to the determination part  604 . 
     The determination part  604  determines a noise detection timing based on the operation states of the respective components of the image forming apparatus  1  inquired by the inquiry part  504 . Further, the determination part  604  stores the determined noise detection timing in the memory  602 , and counts up the noise detection times corresponding to the determined noise detection timing. 
     When the noise detection times counted up by the determination part  604  exceeds a predetermined threshold value (that is, the noise detection times at the same noise detection timing exceed the predetermined threshold value), the communication controller  508  controls the communication interface so as not to perform communication at the noise detection timing at which the noise at the predetermined or higher level influences the communication state. 
     In this manner, the communication state (or noise) is monitored, and the communication is not performed at a timing at which the communication state easily becomes abnormal (or timing at which high degree of noise easily occurs). This arrangement reduces inconvenience that an abnormality in the component of the image forming apparatus  1  influences the communication state to cause abnormal communication state even when actually no communication abnormality occurs. Thus time before the cause of the abnormality is identified can be reduced, and the operating ratio of the image forming apparatus  1  can be increased. 
     The foregoing description of the exemplary embodiment of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The exemplary embodiment was chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.