JP4643410B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus configured to be communicable between an apparatus main body including an image forming unit that forms an image on a sheet and a plurality of paper feeding units that feed the image forming unit.

2. Description of the Related Art Conventionally, there is known an image forming apparatus in which a sheet feeding tray is disposed in an apparatus main body and a sheet feeding apparatus attached to the apparatus main body (see, for example, Patent Documents 1 and 2 below). Further, Patent Document 3 below discloses an image forming apparatus in which a plurality of paper feeding devices configured to be detachable from the apparatus main body have a function of performing serial communication with the apparatus main body. It is disclosed.
Japanese Patent Laid-Open No. 11-188947 Japanese Patent Application Laid-Open No. 11-194560 Japanese Patent No. 3012252

  By the way, when the apparatus main body performs serial communication with a plurality of sheet feeding apparatuses, it is common to perform communication cyclically in a preset order.

  However, in this case, various sensors mounted on the paper feeding device, for example, a paper detection sensor for detecting whether or not the paper has reached a predetermined position, and presence / absence of paper for detecting the presence of paper in the paper feeding device Even when a predetermined state is detected by a sensor or the like, a signal indicating the detection cannot be transmitted to the apparatus main body until the order of the sheet feeding apparatuses is changed.

  As a result, when the apparatus main body controls driving of a roller or the like for conveying a sheet based on these signals transmitted from, for example, a sheet feeding apparatus, the timing for starting and stopping the driving is delayed. As a result, for example, when the paper is folded by colliding with a non-rotating roller, or when a plurality of papers are continuously conveyed to the image forming unit via a predetermined interval, the paper There may be a problem that the interval is not constant. This problem is a serious problem particularly in an image forming apparatus that performs an image forming operation at a high speed. In addition, each said patent document 1-3 does not disclose the solution means with respect to such a subject.

  The present invention has been made in view of the above circumstances, and avoids problems caused by the apparatus main body performing cyclic communication cyclically with a plurality of paper feeding apparatuses in a preset order as much as possible. It is an object of the present invention to provide an image forming apparatus capable of performing the above.

  The invention according to claim 1 is an image forming apparatus configured such that an apparatus main body including an image forming unit that forms an image on a sheet and a plurality of paper feeding units that feed the image forming unit can communicate with each other. Each of the sheet feeding units includes a communication unit that communicates with a communication unit of the apparatus main body, and the apparatus main body performs communication processing with the communication unit of the sheet feeding unit. And a communication control unit that cyclically performs communication processing by the communication unit in a predetermined order set for the communication unit of each paper feeding unit, and the communication control unit includes the communication unit When a communication process needs to be performed between a sheet feeding unit different from the sheet feeding unit in the next order of the sheet feeding unit currently in communication processing, Communication with a paper feed unit that needs to perform the communication process during the communication process with the paper feed unit in the next order It is characterized in that to interrupt the management.

  According to the present invention, when it becomes necessary to perform communication processing with a paper feeding unit different from the paper feeding unit in the next order of the paper feeding unit currently in communication processing, the paper feeding unit currently in communication processing Communication processing with the paper feeding unit that needs to perform the communication processing is interrupted between the communication processing with the paper feeding unit corresponding to the next order. It is possible to suppress as much as possible a delay in communication processing with the sheet feeding unit that has to be performed.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the communication process to be interrupted is a communication process related to a paper feed command.

  According to the present invention, it is possible to suppress the delay of the communication processing related to the paper feed command as much as possible.

According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the paper feeding unit includes a paper arrival sensor for detecting whether or not the paper being fed has reached a predetermined detection position. the communication control unit from the paper feed section necessary to perform the communication process has occurred, after receiving a signal indicating that reaching the predetermined detection position by the paper in the paper feeding the paper arrival sensor, the paper feed The paper feed unit is removed from the communication target for a period of time from when it is detected by the paper arrival sensor that the paper has reached a predetermined detection position until the paper disappears from the paper feed unit. It is characterized by this.

  According to the present invention, after receiving a signal indicating that the paper being fed has reached a predetermined detection position by the paper arrival sensor from the paper feed unit that has been determined to need to perform the communication process, Since a period (the predetermined period) in which it is not necessary to perform communication processing between the paper feeding unit and the apparatus main body occurs, communication processing is performed between the other paper feeding units and the apparatus main body during this period. By doing so, the cycle of communication processing performed between the other sheet feeding unit and the apparatus main body is shortened, and the exchange of information between the apparatus main body and the other sheet feeding unit is performed at a shorter period. It can be carried out.

In addition, according to the present invention, the period during which communication processing need not be performed between the sheet feeding unit and the apparatus main body determined to have been required to perform communication processing is accurately set.

  According to the present invention, necessary communication processing is performed even when the paper feed unit is excluded from the communication target.

  According to the present invention, since the delay of the communication process with the paper feeding unit that needs to perform the communication process is suppressed as much as possible, the start and stop of the driving of the roller that conveys the sheet is stopped as in the past. When the execution timing is delayed, the paper breaks when it collides with a non-rotating roller, or the paper interval when a plurality of papers are continuously conveyed to the image forming unit is not constant. It is possible to avoid problems such as

  Hereinafter, an embodiment of a printer which is an example of an image forming apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a side view showing the internal configuration of the printer according to the present embodiment.

  As shown in FIG. 1, the printer 1 includes an image forming unit 2, a paper supply unit 3 positioned below the image forming unit 2, and a paper discharge unit 4 positioned above the image forming unit 2. .

  The image forming unit 2 forms an image on a recording sheet based on image data transmitted from a personal computer (not shown) that is communicably connected to the printer, for example. And a transfer roller 6. The transfer roller 6 is configured to transfer the toner image formed on the surface of the photosensitive drum 5 onto the sheet by sandwiching the sheet with the photosensitive drum 5.

  Although not shown in detail, the image forming unit 2 includes a charging unit disposed opposite to the circumferential surface of the photosensitive drum 5, and a downstream side of the charging unit on the circumferential surface of the photosensitive drum 5. The exposure unit disposed oppositely, the developing unit disposed downstream of the exposure unit and opposed to the circumferential surface of the photosensitive drum 5, and the downstream side of the developing unit and disposed around the photosensitive drum 5. A cleaning unit or the like disposed to face the surface is also provided.

  A registration roller pair 7 and a registration sensor 8 for aligning the toner image formed on the surface of the photosensitive drum 5 and the leading end position of the paper are installed at predetermined positions upstream of the photosensitive drum 5 and the transfer roller 6. Yes.

  The registration sensor 8 is for detecting whether or not the sheet reaches the detection position of the sensor at a predetermined position downstream of the registration roller pair 7, and indicates when the sheet reaches the detection position. The signal is output to a main body control unit 53 (see FIG. 2) described later. The main body control unit 53 receives this arrival signal, sets an appropriate conveyance start timing by the registration roller pair 7, and causes the registration roller pair 7 to convey the sheet between the photosensitive drum 5 and the transfer roller 6. .

  At a predetermined position on the upstream side of the photosensitive drum 5 and the transfer roller 6, a fixing unit 11 that heats the recording paper on which the toner image is transferred and fixes the toner image on the recording paper is installed. The heat roller 9 and the pressure roller 10 are provided so as to face each other vertically. The paper on which the image has been formed by the photosensitive drum 5 and the transfer roller 6 is fixed by a heat treatment by being pressed and nipped while being heated by the heat roller 9 and the pressure roller 10, and a stable image is formed on the paper. Is done. The paper on which the fixing process has been completed is discharged toward the upper paper discharge unit 4 through the paper discharge conveyance path 12.

  The paper supply unit 3 includes a main feeder 13 fixedly installed on the printer main body 1a and a plurality of option feeders 14 to 17 configured to be detachable from the printer main body 1a. The option feeder is an example of a sheet feeding unit.

  The main feeder 13 is configured to detect a presence / absence of a paper on the placement table 18, a placement table 18 for placing the paper, a paper feed roller 19 that feeds the paper placed on the placement table 18 one by one. A paper sensor 20.

  On the other hand, the option feeders 14 to 17 are configured to be detachable in an upper and lower multi-stage manner in an option feeder mounting space formed in the printer main body 1a, and a mounting table 21 to 24 for mounting paper and a mounting table 21 Feed rollers 25 to 28 for feeding the sheets placed on the sheet 24 one by one, transport roller pairs 29 to 32 for feeding the sheets fed by the sheet feed rollers 25 to 28, and on the placement tables 21 to 24 Paper sensors 33 to 36 for detecting the presence or absence of paper and paper arrival sensors 37 to 40 for detecting the passage state of the paper at a predetermined detection position are provided.

  When the option feeders 14 to 17 are attached to the printer main body 1a, they are electrically connected by the connectors 54 to 57, and can communicate with the main body control unit 53 via the connectors 54 to 57.

  The paper discharge unit 4 is provided at a position above the image forming unit 2, and is installed in the vicinity of the paper placement unit 41 on which the sheets after the fixing process are stacked and the discharge port of the paper placement unit 41. A discharge roller pair 42 is provided.

  In the printer 1 having the above-described configuration, paper is supplied from the main feeder 13 or the optional feeders 14 to 17, and is conveyed to the image forming unit 2 through the conveyance path 43. Thereafter, the sheet on which the image is formed by the image forming unit 2 is discharged to the sheet discharge unit 4.

  FIG. 2 is a block diagram showing an electrical configuration of the printer 1 when all of the option feeders 14 to 17 are mounted on the printer main body 1a.

  The printer main body 1 a includes a communication unit 52 that communicates various signals with the option feeders 14 to 17, and a main body control unit 53. The main body control unit 53 controls operation of the entire apparatus. For example, a ROM (Read Only Memory) that stores a control program for controlling the operation of the printer 1 and a RAM (Random) that temporarily stores data. (Not shown in the figure) and a microcomputer for reading out a control program from the ROM and executing it.

  The main body control unit 53 also drives the paper feed rollers 25 to 28, the transport roller pairs 29 to 32, the paper feed rollers 25 to 28 and the transport roller pairs 29 to 32 provided in the option feeders 14 to 17, respectively. The motor has a function of controlling the operation of a paper feed clutch for transmitting and interrupting the driving force of the motor.

  Each of the option feeders 14 to 17 includes communication units 44 to 47 that communicate various signals with the main body control unit 53 and control units 48 to 51. The control units 48 to 51 control the operation of the entire option feeder. For example, the control units 48 to 51 control the operations of the transport roller pairs 29 to 32 and the paper feed rollers 25 to 28 based on a command from the main body control unit 53. ROM (Read Only Memory) for storing control programs and the like, an unillustrated storage unit such as RAM (Random Access Memory) for temporarily storing data, and a microcomputer that reads and executes control programs from the ROM It is composed of

  Next, communication processing performed between the printer main body 1a and the option feeders 14 to 17 will be described. FIG. 3 is a diagram illustrating a harness connection mode between the printer main body 1a and the option feeder or a harness connection mode between the option feeder and the option feeder.

  The option feeders 15 to 17 can communicate with the main body control unit 53 via an option feeder located above the option feeder. That is, the printer main body 1a and the option feeder 14, the option feeder 14 and the option feeder 15, the option feeder 15 and the option feeder 16, and the option feeder 16 and the option feeder 17 are connected in a harness connection manner as shown in FIG. . In the following description, in the connection relationship of each set, the output side of the output signal of the printer main body 1a is referred to as a master, and the reception side of the output signal is referred to as a slave.

  The master and the slave are a signal line for a select signal (OPSEL2, OPSEL1, OPSEL0), a signal line for a communication ready signal (READYN), a signal line for a slave, The signal line for the reception data signal (OPSDO), the signal line for the slave transmission data signal (OPSDI), and the signal line for the synchronous clock signal (OPSCLK) are connected, and three-wire serial communication is performed. It is like that.

  FIG. 4 is a diagram showing input signals of the option feeders 14 to 17 with respect to select signals (OPSEL2, OPSEL1, OPSEL0) output from the main body control unit 53 in this connection mode.

  As shown in FIG. 4, when a select signal of (1, 0, 0), for example, is output from the printer main body 1a as a select signal (OPSEL2, OPSEL1, OPSEL0), (1,0, 0) is output to the option feeder 14. ), (0,0,0) signal to the option feeder 15, (0,0,1) signal to the option feeder 16, and (0,1,1) signal to the option feeder 17. A signal is input.

  In the present embodiment, the option feeders 14 to 17 recognize that they have been set as the communication partner of the printer main body 1a when receiving the signal (1, 0, 0). In the above example, the option feeder 14 is set as the communication partner of the printer main body 1a. Therefore, the select signal when each of the option feeders 14 to 17 becomes a communication partner of the printer main body 1a is as shown in FIG.

  When the option feeders 14 to 17 are set as communication partners of the printer main body 1a, they communicate with the printer main body 1a as follows. FIG. 6 is a time chart showing a select signal “SELECT”, a communication ready signal “READY”, a clock signal “OPSCLK”, a transmission data signal “OPSDI”, and a reception data signal “OPSDO”.

  The option feeder and the printer main body 1a transmit and receive data in units of 4 bytes (8 bits × 4), for example. Data transmission / reception is performed simultaneously for each 1-bit clock, with the most significant bit (MSB) as the head in synchronization with the clock signal “OPSCLK”. The transmission data is output in synchronization with the falling edge of the clock, and the reception data is captured in synchronization with the rising edge of the clock. The option feeder selected by the select signal controls permission to send a clock from the printer body by the communication ready signal “READYN”. Information such as a paper feed clutch, rotation control of a pair of conveyance rollers, a paper size, a paper sensor, a paper arrival sensor, and the like are transmitted and received as a 4-byte signal.

  When the select signal becomes active as indicated by an arrow A and enters a receivable state, the option feeders 14 to 17 make the communication ready signal “READYN” true as indicated by an arrow B. The option feeders 14 to 17 invert the communication ready signal “READYN” as indicated by an arrow D as soon as the next reception becomes possible after receiving a 1-byte signal as indicated by an arrow C. As indicated by arrow E, the printer main body 1a starts transmission of the next clock according to this reversal operation.

  After receiving a signal of a predetermined number of bytes, the option feeders 14 to 17 set the serial communication data line to “L (low)” if the received content is received normally, and to “H (high) if the reception is abnormal. ) ”, And the communication ready signal“ READYN ”is inverted as indicated by an arrow F. The printer main body 1a cancels the selected state of the option feeder as indicated by an arrow G in accordance with the reversing operation.

  The option feeders 14 to 17 set the data line and the communication ready signal “READYN” to a high impedance state as indicated by an arrow H when the selection state by the printer main body 1 a is released. In response to the communication ready signal “READYN” being set to the high impedance state, the printer main body 1a starts transmission of the next signal. When each of the option feeders 14 to 17 is selected as a communication partner of the printer main body 1a, the above-described communication is performed with the printer main body 1a.

  By the way, this embodiment is characterized in that the order of option feeders that communicate with the printer main body 1a is set as follows. FIG. 7 is a diagram for explaining the communication order of the option feeders 14 to 17 in the present embodiment. In FIG. 7, (1) to (4) correspond to the option feeders 14 to 17, and The square means that communication processing as shown in FIG. 6 is performed. Moreover, FIG. 8 is a figure for demonstrating the communication order of the conventional option feeders 14-17.

  As shown in FIG. 8, conventionally, as indicated by an arrow J, when the main body control unit 53 determines that it is necessary to feed paper from the option feeder 15 during communication processing with the option feeder 16, for example, The sheet feeding command to the option feeder 15 is performed after the communication processing with the option feeders (4) and (1).

  On the other hand, in this embodiment, as shown by an arrow O in FIG. 7, a paper feed command for the option feeder 15 is performed after the communication processing of the option feeder 16 (communication processing with the option feeder 16 and the option feeder 17. Interrupt the communication process). After that, communication processing is executed cyclically from the option feeder 17.

  On the other hand, the option feeder 15 performs a paper feeding operation in accordance with a paper feeding command from the main body control unit 53, and when a paper arrival signal is output from the paper arrival sensor 38, as shown by an arrow P in FIG. Later, when the order in which the option feeder 15 performs communication processing with the main body control unit 53 comes, a paper arrival signal (paper arrival sensor 38) indicating that a paper arrival signal is output from the paper arrival sensor 38. Is output to the main body control unit 53.

  As shown in FIG. 7, when the main body control unit 53 receives the paper arrival signal from the option feeder 15, the main body control unit 53 removes the option feeder 15 from the communication target for a predetermined period T from the reception time point, and the option feeders 14, 16,. A communication process is executed cyclically with the terminal 17.

  The predetermined period (time) T is expressed by the following equation (1).

T = (LD) / m (1)
L: length of paper D: distance from paper feed standby position to detection position of paper arrival sensor 38 m: linear speed (paper transport speed)
The paper feed standby position is a position immediately before paper feed is started, and is a position corresponding to the point Pw shown in FIG. For simplicity of explanation, as shown in FIG. 9, assuming that the paper transport direction from the option feeders 14 to 17 and the detection positions of the paper arrival sensors 37 to 40 are on the same straight line, (L− D) corresponds to the distance x shown in FIG. 9, that is, during the predetermined period T, after the leading edge of the paper reaches the detection position of the paper arrival sensors 37 to 40, the paper is placed on the mounting tables 21 to 24. It corresponds to the period until it disappears.

  As described above, the option feeder 15 is excluded from the communication target during the predetermined period T. The option feeder 15 is not connected to the option feeder 15 during the predetermined period after the paper reaches the detection position of the paper arrival sensor 38. This is because it is considered that communication should be performed more frequently with the other option feeders 14, 16, and 17 while there is no change in the state related to paper feeding and there is no need to perform communication processing.

  However, if it is necessary to communicate with the option feeder 15 during the predetermined period T, communication with the option feeder 15 is executed even during the predetermined period T.

  As described above, when there is a need to perform communication processing related to a paper feed command with an option feeder that is not in the next order of the option feeder being processed, next to the option feeder currently being processed. Since communication processing with the printer main body 1a is executed (interrupted), it is possible to suppress a delay in paper feed timing as much as possible.

  That is, in the conventional communication method shown in FIG. 8, since the printer main body 1a sequentially performs communication processing with the option feeders 14 to 17, it is necessary to feed paper from the option feeder 15 during the communication processing with the option feeder 16. Even if there is, when the order of the next option feeder 15 comes as shown by the arrow K in FIG. 8, the paper feeding command is received from the printer main body 1a and the paper feeding is started.

  Therefore, as can be seen from the comparison between the arrow P in FIG. 7 and the arrow L in FIG. 8, the timing at which the paper arrival signal is output to the main body control unit 53 is determined by the main body control unit 53 with respect to the option feeder 15. Is significantly delayed from the timing at which it is determined to be performed (the timing indicated by the arrow J). Accordingly, when the main body control unit 53 starts or stops driving the transport roller pair 29 of the option feeder 14 positioned on the upper stage of the option feeder 15 based on the paper arrival signal, the execution timing is set. Due to the delay, the driving start timing of the transport roller pair 29 is delayed, and the paper is broken by colliding with the transport roller pair 29 which is not rotating, and a plurality of papers are separated at intervals. When continuously trying to convey the image to the image forming unit 2, there may be a problem that the interval between the sheets is not constant.

  On the other hand, in the present embodiment, the timing at which the paper arrival signal is output to the main body control unit 53 should be set so that the main body control unit 53 issues a paper feed command to the option feeder 15 as compared with the conventional case. Since it is possible to approach the determined timing (arrow O), it is possible to avoid the occurrence of the above-described problems as much as possible.

  Further, after interrupting the communication process with the option feeder which is not in the next order, the communication process with the printer main body 1a is cyclically performed in order from the option feeder in the next order, and the communication process is interrupted. After the option feeder outputs a signal indicating that the paper has reached the detection position of the paper arrival sensor to the printer main body 1a (after the timing indicated by the arrow P), the time calculated by the equation (1) elapses. Since communication processing is not performed between the option feeder and the printer main body 1a (the option feeder is excluded from the communication target of the printer main body 1a), communication performed between other option feeders and the printer main body 1a. The processing cycle is shortened. As a result, transmission / reception of signals between the other option feeder and the printer main body can be performed in a shorter cycle.

  Further, when it is necessary to perform communication processing with an option feeder during a period when an option feeder is excluded from communication with the printer main body 1a, the option feeder and the printer main body are connected. Since the communication process is interrupted, the necessary communication process can be surely executed.

  Note that this case includes modifications described in the following [1] and [2] in addition to the above embodiment or instead of the above embodiment.

  [1] The communication process to be interrupted is not limited to the communication process related to the paper feed command, and may be another communication process.

  [2] Although a printer has been described as an example of an image forming apparatus, the present invention is not limited to these, and a copier, a multifunction machine, or the like may be used.

1 is a side view showing an internal configuration of a printer which is an example of an image forming apparatus according to the present invention. FIG. 3 is a block diagram illustrating an electrical configuration of the printer when all option feeders are mounted on the printer body. It is a figure which shows the harness connection aspect of a printer main body and an option feeder, or the harness connection aspect of an option feeder and an option feeder. FIG. 4 is a diagram showing input signals of each option feeder for select signals (OPSEL2, OPSEL1, and OPSEL0) output from the main body control unit in the connection mode shown in FIG. FIG. 6 is a diagram illustrating a select signal when each option feeder is a communication partner of the printer main body. 4 is a time chart showing a select signal “SELECT”, a communication ready signal “READY”, a clock signal “OPSCLK”, a transmission data signal “OPSDI”, and a reception data signal “OPSDO”. It is a figure for demonstrating the communication order of the option feeder in this embodiment. It is a figure for demonstrating the communication order of the conventional option feeder. It is explanatory drawing of the predetermined period which removes an option feeder from communication object.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer 1a Printer main body 2 Image forming part 3 Paper supply part 14-17 Option feeders 21-24 Mounting stand 25-28 Paper feed roller 29-32 Carrying roller pair 33-36 Paper sensor 37-40 Paper arrival sensor 44-47 Communication 48 to 51 Control unit 52 Communication unit 53 Main unit control unit

Claims (3)

An image forming apparatus configured to be able to communicate with an apparatus main body including an image forming unit that forms an image on a sheet, and a plurality of paper feeding units that feed the image forming unit,
Each of the paper feeding units
A communication unit that communicates with the communication unit of the apparatus body;
The apparatus main body is
A communication unit that performs communication processing with the communication unit of each of the sheet feeding units;
A communication control unit that cyclically performs communication processing by the communication unit in a predetermined order set for the communication unit of each sheet feeding unit,
When the communication control unit needs to perform communication processing between the communication unit and a paper feeding unit different from the paper feeding unit in the next order of the paper feeding unit currently in communication processing, The communication processing with the paper feeding unit that needs to perform the communication processing is interrupted between the communication processing with the paper feeding unit and the communication processing with the paper feeding unit in the next order. Image forming apparatus.   The image forming apparatus according to claim 1, wherein the communication process to be interrupted is a communication process related to a paper feed command. The paper feed unit includes a paper arrival sensor for detecting whether or not the paper being fed has reached a predetermined detection position,
Said communication control unit, from the paper feed section necessary to perform the communication process has occurred, after the sheet being fed has received a signal indicating that reaching the predetermined detection position by the paper arrival sensor, during feeding The paper feeding unit is removed from the communication target for a period corresponding to the time from when the paper arrival sensor detects that the paper has reached a predetermined detection position until the paper is no longer on the paper feeding unit. The image forming apparatus according to claim 2.

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