JP3854465B2 - Scanner control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a scanner control device that controls the operation of a scanner, and particularly relates to improvements in scanner reset control.
[0002]
[Prior art]
In general, in an image forming apparatus including a scanner, a control unit having a microcomputer configuration including a CPU and a drive circuit for driving the scanner are connected, and the operation of the scanner is controlled by the control unit. .
[0003]
For example, in the example described in Japanese Patent Application Laid-Open No. 2000-23483 filed with the title of a scanner motor control device, a control circuit having a CPU is provided to control the operation of the scanning motor drive circuit, and the motor drive The voltage supplied to the circuit is monitored, and when an abnormality occurs due to a power failure or the like, the CPU of the control circuit is reset to stop the operation of the scanner. The control circuit in this example is a single unit.
[0004]
[Problems to be solved by the invention]
When the control unit as the control circuit is a single unit, it can be formed on one board (substrate), and the influence of noise can be reduced. However, in an image forming apparatus such as a copying machine, the control unit includes a scanner control unit that drives and controls only the scanner, and a system control unit that monitors and controls the operation of the entire image forming apparatus, due to the arrangement of components. In some cases, each of them is mounted on a board provided separately and connected with a cable.
[0005]
In this case, in the configuration in which the CPU is provided in both the scanner control unit and the system control unit, reset management can be performed by the CPU of the scanner control unit that directly controls the scanner. Will not recognize. However, the cost increases because the number of CPUs increases.
[0006]
In order to reduce the cost, the CPU of the scanner control unit is omitted, the CPU is provided only in the system control unit, and the reset signal is supplied from the CPU of the system control unit to the scanner control unit via a cable. A cable connecting the control unit and the scanner control unit picks up noise, and the scanner control unit may erroneously recognize the noise as a reset signal. In this case, since the system control unit does not output a reset signal, it does not recognize that the scanner control unit is in a reset state. In this state, various commands are output from the system control unit to the scanner control unit, and the scanner control unit may run away.
[0007]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to reduce the cost without providing a CPU in the scanner control unit so that the reset control of the scanner control unit can be correctly performed collectively by the system control unit having the CPU.
[0008]
A further object of the present invention is to reduce the number of signal lines between the system control unit and the scanner control unit.
[0009]
[Means for Solving the Problems]
According to the first aspect of the present invention, a scanner control unit that does not have a CPU and controls driving of a scanner by a predetermined command signal from an external control unit , and is output from the external control unit to the scanner control unit when an abnormality occurs. When the reset signal is received, the scanner control unit is set in a reset state, and then the reset control unit maintains the reset state until the scanner control unit receives a reset release command, and the scanner control unit is operated by the reset state maintenance unit. Reset state notifying means for notifying the external control unit of the state when the reset state is maintained.
[0010]
Therefore, the reset control of the scanner control unit can be collectively performed by the external control unit . At that time, it is possible to notify the external control unit by the reset state communication means whether or not the scanner control unit is maintained in the reset state, so the external control unit recognizes the state where the abnormality has occurred in the scanner control unit. It becomes possible to do.
[0011]
According to a second aspect of the present invention, in the first aspect of the invention, the scanner control unit rejects a command that does not accept a command signal other than a reset release command output from the external control unit when the reset state is maintained. Means.
[0012]
Therefore, before the scanner control unit is erroneously maintained in the reset state due to the influence of noise and the scanner control unit notifies the external control unit that the reset state has been maintained, the external control unit is not a reset release command. Even if the command signal is issued, the runaway of the scanner control unit can be prevented.
[0013]
According to a third aspect of the present invention, in the first or second aspect of the invention, the reset state notifying unit releases the reset state when a reset release command is output from the external control unit to the scanner control unit. The received response is notified to the external control unit.
[0014]
Therefore, the external control unit can recognize the state in which the scanner control unit has returned from the reset state to the reset release state.
[0015]
According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the reset state notifying unit uses a communication data line for reading information of the scanner control unit by the external control unit. Notify reset status.
[0016]
Therefore, it is possible to read the reset / reset release information of the scanner control unit by the external control unit using the communication data line for reading the information of the scanner control unit by the external control unit .
[0017]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described with reference to FIGS. 1 is a longitudinal front view schematically showing the configuration of a copying machine, FIG. 2 is a block diagram schematically showing an electrical connection structure of a scanner control device, and FIG. 3 is a signal time when a reset is normally performed. FIG. 4 is a time chart of signals when the reset is abnormally performed.
[0018]
This embodiment will be described as a scanner control device in a copying machine. In FIG. 1, reference numeral 1 denotes a copying machine. The copying machine 1 includes a printer 2 and a scanner 3 disposed on the printer 2. The printer 2 forms an electrostatic latent image on the photosensitive member 4, develops the electrostatic latent image as a toner image, transfers the toner image onto a sheet fed from the sheet feeding unit 5, and transfers the toner image onto the sheet. This is a known electrophotographic printer configured to fix the transferred image by the fixing roller 6.
[0019]
The scanner 3 is a known scanner that reads an original image by the optical system 7 and inputs it to the CCD 8, performs image processing on the image data output from the CCD 8, and outputs the processed image data to the printer 2.
[0020]
Next, the scanner control device 9 will be described with reference to FIG. Reference numeral 10 denotes a system control unit provided in the printer 2, and 11 denotes a scanner control unit provided in the scanner 3. These control units 10 and 11 are formed as circuits on different boards (substrates). The system control unit 10 updates and writes variable data such as a CPU for monitoring and controlling the operation of the entire copying machine 1, a ROM in which fixed data such as a program executed by the CPU is written, and work data. It has a RAM and functions as a microcomputer. The scanner control unit 11 includes a drive circuit for controlling the operation of the scanner 3 and does not have a CPU. The system control unit 10 and the scanner control unit 11 are connected to each other by a cable. This cable notifies the system control unit 10 that it is in a reset state when a reset signal line 12 for outputting a reset signal A to the scanner control unit 11 from the system control unit 10 and the scanner control unit 11 receives the reset signal. A reset response signal line 13, a communication data line 14 for outputting transmission data including various command signals and reset release commands from the system control unit 10 to the scanner control unit 11, and information on the scanner control unit 11 are transmitted to the system control unit 10. Including a communication data line 15 to be read by. The system control unit 10 and the scanner control unit 11 are connected by a common ground line 16 that is grounded.
[0021]
In such a configuration, in the copying machine 1, a document is placed on the contact glass of the scanner 3, and reading of a document image is started by pressing a start button of an operation unit (not shown). Print out. This series of processing is performed by executing the program in the ROM after the CPU of the system control unit 10 recognizes the input of the start button. The scanner control unit 11 reads the document image by driving the optical system 7 in the scanning direction under the control of the CPU of the system control unit 10.
[0022]
The CPU of the system control unit 10 that monitors the operation of each unit outputs a reset signal A for a certain period of time as shown in FIG. As a result, the scanner control unit 11 is reset. This reset state is maintained until a reset release command is received from the system control unit 10. During this time, the scanner control unit 11 is maintained in a stopped state under the control of the system control unit 10.
[0023]
As shown in FIGS. 2 and 3, in the present embodiment, the scanner control unit 11 sends a signal B indicating that it is in a reset state to the system control unit 10 (function as a reset state communication unit). By configuring, it is possible to notify the system control unit 10 by the signal B whether or not the scanner control unit 11 is maintained in the reset state. For this reason, the system control unit 10 can recognize a state in which an abnormality has occurred in the scanner control unit 11. At this time, since the CPU of the system control unit 10 monitors the state of each unit and does not execute the next processing unless the conditions are satisfied, the runaway of the scanner control unit 11 can be prevented.
[0024]
Further, the reset state notifying unit has a function of notifying the system control unit 10 of a response to that effect when a reset release command is output from the system control unit 10 to the scanner control unit 11. The state in which the control unit 11 returns from the reset state to the reset release state can be recognized by the system control unit 10.
[0025]
Here, consider a case where the cable connecting the system control unit 10 and the scanner control unit 11 picks up noise and the scanner control unit 11 is erroneously reset due to the noise. In this case, since the system control unit 10 receives the signal B indicating that the reset state is maintained from the scanner control unit 11 even though there is no history of outputting the reset signal, the CPU of the system control unit 10 determines that it is abnormal. . After that, the reset signal A is output to the scanner control unit 11 again. Of the reset signal A in FIG. 4, a signal having a short pulse width is an erroneous signal due to noise, and a signal having a constant pulse width thereafter is a regular reset signal. The scanner controller 11 maintains the reset state until a reset release command is accepted, whether it is accidentally reset due to noise or it is reset by the normal reset signal A, so that the scanner controller 11 and the scanner 3 run away. Can be prevented.
[0026]
In this case, the scanner control unit 11 is provided with a function that does not accept a command signal other than a reset release command output from the system control unit 10 when the reset state is maintained (function as a command rejection unit), thereby controlling the scanner. Until the scanner controller 11 informs the system controller 10 that the unit 11 has been erroneously maintained in the reset state due to the influence of noise and has been maintained in the reset state, the system controller 10 is in a state other than the reset release command. Even if the command signal is issued, the runaway of the scanner control unit 11 can be prevented.
[0027]
Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as those in the above embodiment are denoted by the same reference numerals, and the description thereof is omitted. FIG. 5 is a block diagram schematically showing an electrical connection structure of the scanner control device.
[0028]
The reset state notifying means in the present embodiment is configured to notify the reset state using the communication data line 15 for reading information of the scanner control unit 11 by the system control unit 10.
[0029]
In such a configuration, the system control unit 10 can read the reset / reset release information of the scanner control unit 11 by using the communication data line 15 that reads the information of the scanner control unit 11 by the system control unit 10. . Therefore, the number of signal lines connecting the system control unit 10 and the scanner control unit 11 can be reduced.
[0030]
【The invention's effect】
According to the first aspect of the present invention , a scanner control unit that does not have a CPU and controls driving of the scanner by a predetermined command signal from the external control unit, and is output from the external control unit to the scanner control unit when an abnormality occurs. A reset maintaining unit that resets the scanner control unit when receiving a reset signal, and then maintains the reset state until the scanner control unit receives a reset release command; and the scanner control unit includes the reset state maintaining unit. By providing the reset state notifying means for notifying the external control unit of the state when the reset state is maintained by the above, a scanner control unit is not provided with a CPU, so that the cost can be reduced. In addition, even if an erroneous reset signal is input due to noise after entering the reset state, the reset state of the scanner control unit is maintained until a reset release command output from another signal destination is received from the external control unit. The reset control of the scanner control unit can be correctly performed collectively by the external control unit.
[0031]
According to a second aspect of the invention , in the first aspect of the invention, the scanner control unit rejects a command that does not accept a command signal other than a reset release command output from the external control unit when the reset state is maintained. Since the scanner control unit is erroneously maintained in the reset state due to the influence of noise and the scanner control unit notifies the external control unit that the reset state has been maintained, the external control unit Even when an instruction signal other than the reset release command is issued, the runaway of the scanner control unit can be prevented.
[0032]
According to a third aspect of the invention, in the first or second aspect of the invention, the reset state notifying unit releases the reset state when a reset release command is output from the external control unit to the scanner control unit. The external control unit is notified of the response, so that the external control unit can recognize that the scanner control unit has returned from the reset state to the reset release state, and thus the scanner control unit returns to the reset release state. It is possible to prevent the runaway by recognizing the detected state and controlling the operation of the scanner control unit by a command from the external control unit.
[0033]
According to the invention described in claim 4, in the invention described in any one of claims 1 to 3, the reset state notifying means resets using the communication data line for reading the information of the scanner controller by the external controller. since the notification of the state by using a communication data line for reading the information of the scanner control unit in the external control unit, it can read information of the reset / reset release of the scanner control unit in the external control unit, thereby, The number of signal lines connecting the external control unit and the scanner control unit can be reduced.
[Brief description of the drawings]
FIG. 1 is a longitudinal front view schematically showing a configuration of a copying machine according to a first embodiment of the present invention.
FIG. 2 is a block diagram schematically showing an electrical connection structure of a scanner control device.
FIG. 3 is a time chart of signals when a normal reset is applied.
FIG. 4 is a time chart of signals when an abnormal reset is applied.
FIG. 5 is a block diagram schematically showing an electrical connection structure of a scanner control device according to a second embodiment of the present invention.
[Explanation of symbols]
3 Scanner 10 System Control Unit 11 Scanner Control Unit 15 Communication Data Line

Claims (4)

A scanner control unit that does not have a CPU and controls the drive of the scanner by a predetermined command signal from an external control unit;
When the reset signal output to the scanner control unit is received from the external control unit when an abnormality occurs, the scanner control unit is set in a reset state, and then the reset state is set until the scanner control unit receives a reset release command. Reset maintaining means to maintain;
A scanner control apparatus comprising: a reset state notifying unit that notifies the external control unit of the state when the scanner control unit is maintained in a reset state by the reset state maintaining unit.   The scanner control device according to claim 1, wherein the scanner control unit includes command rejection means that does not accept a command signal other than a reset release command output from the external control unit when the reset state is maintained. The reset state notifying unit notifies the external control unit of a response that the reset state is released when a reset release command is output from the external control unit to the scanner control unit. The scanner control device described.   The scanner control device according to claim 1, wherein the reset state notification unit notifies the reset state using a communication data line for reading information of the scanner control unit by the external control unit.

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