Abstract:
An inkjet recording device includes a carriage including a print head for firing ink droplets onto a recording medium from a nozzle; a carriage driving unit configured to drive the carriage; an openable cover configured to cover a moving area of the carriage; a cover lock member configured to lock the cover to a housing; a lock control unit configured to control lock and release of the lock of the cover by the cover lock member; a lock releasing unit configured to request the lock control unit to release the lock; and a carriage power control unit configured to control opening and closing of a power supplying path to the carriage driving unit. The lock control unit causes the cover lock member to release the lock if the lock releasing unit is operated and the carriage power control unit opens the power supplying path to the carriage driving unit.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority to and incorporates by reference the entire contents of Japanese Patent Application No. 2012-065475 filed in Japan on Mar. 22, 2012. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an inkjet recording device, and a method of releasing a cover lock of the inkjet recording device. 
     2. Description of the Related Art 
     When a recording sheet gets jammed or a carriage operation error occurs in an inkjet recording device, an operator opens a cover and inserts a hand to remove the recording sheet, or moves a carriage to its home position. If the carriage is moved then, it can hit a hand of the operator or the operator can get his/her finger caught therein, which is significantly dangerous. If the carriage keeps printing operation when the cover is opened during printing, the operator may touch the carriage with his/her hand unintentionally, which is significantly dangerous. 
     Then, it is already known that the movement of a carriage is stopped in response to the detection of opening of a cover at the moment when the cover is opened, in order to avoid the danger. 
     Moreover, it is also already known that a cover and a housing are locked so that an operator cannot open the cover until printing is finished or an error is detected. 
     However, the conventional inkjet recording device does not necessarily guarantee the safety because there occurs a time difference between the detection of opening of a cover and the stop of a carriage, depending on detection timing, etc. There is a possibility of failure or malfunction, and the carriage is not necessarily stopped. Therefore, the safety is not sufficient. Even if the cover and the housing are locked, it is possible that when the lock is released and the cover is opened, the carriage is moved due to malfunction of the carriage. In the case where the carriage is stopped in the center of the housing when an error is detected, the carriage is possibly moved when the cover is opened and a hand is inserted in the housing, which can be a problem in terms of safety. 
     Japanese Patent Application Laid-open No. 2006-142608 discloses a printer and a printing control method. The printer includes an openable cover that covers a moving area of a printing head, a cover state detecting unit that detects the opening and closing of the cover, a printing state detecting unit that detects a printing state, and a lock unit that locks the cover to a housing. For the safe operation of an operator, the cover is locked to the housing during printing operation so that the cover is prevented from being opened, and the lock is released when printing is finished or an error is detected so that the cover can be opened. 
     According to the conventional technique as described above, the cover is locked to the housing so that the cover cannot be opened during printing operation. However, in the conventional technique, the carriage is possibly moved due to malfunction of the carriage when the lock is released and the cover is opened. Moreover, in the case where the carriage is stopped in the center of the housing when an error is detected, the carriage is possibly moved when the cover is opened and a hand is inserted in the housing. Thus, the problems regarding the safety have not been solved sufficiently. 
     Therefore, there is a need to provide an inkjet recording device that is excellent in safety and allows an operator to use it safely without a risk of injury due to the movement of the carriage. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to at least partially solve the problems in the conventional technology. 
     According to an embodiment, there is provided an inkjet recording device that includes a carriage including a print head for recording by firing an ink droplet onto a recording medium from a nozzle; a carriage driving unit configured to drive the carriage; an openable cover configured to cover a moving area of the carriage; a cover lock member configured to lock the cover to a housing of the inkjet recording device; a lock control unit configured to control lock of the cover and release of the lock of the cover by the cover lock member; a lock releasing unit configured to request the lock control unit to release the lock of the cover; and a carriage power control unit configured to control opening and closing of a power supplying path to the carriage driving unit. The lock control unit causes the cover lock member to release the lock of the cover if the lock releasing unit is operated and the carriage power control unit opens the power supplying path to the carriage driving unit. 
     According to another embodiment, there is provided a method of releasing a cover lock of an inkjet recording device that includes a carriage including a print head for recording by firing an ink droplet onto a recording medium from a nozzle, a carriage driving unit configured to drive the carriage, an openable cover configured to cover a moving area of the carriage, a cover lock member configured to lock the cover to a housing of the inkjet recording device, a lock control unit configured to control lock of the cover and release of the lock of the cover by the cover lock member, a lock releasing unit configured to request the lock control unit to release the lock of the cover, and a carriage power control unit configured to control opening and closing of a power supplying path to the carriage driving unit. The method includes causing, by the lock control unit, the cover lock member to release the lock of the cover if the lock releasing unit is operated and the carriage power control unit opens the power supplying path to the carriage driving unit. 
     The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram schematically illustrating an entire configuration of an inkjet recording device; 
         FIG. 2  is a block diagram illustrating a system configuration of the inkjet recording device; 
         FIG. 3  is a circuit diagram illustrating a circuit for power supply to a carriage driving unit; 
         FIG. 4  is a diagram illustrating an interlock switch; 
         FIG. 5  is a diagram schematically illustrating an entire configuration of a cover lock unit; 
         FIG. 6  is a flowchart illustrating control procedures in a system control unit when a cover lock releasing button is pushed while a cover is locked; 
         FIG. 7  is a flowchart illustrating control procedures by a system control unit after an error occurred during printing; 
         FIG. 8  is a flowchart illustrating control procedures the system control unit when a power supply is turned on; and 
         FIG. 9  is a flowchart illustrating control procedures by the system control unit when maintenance service is provided. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An embodiment of an inkjet recording device of the invention is described with reference to the accompanying drawings. 
       FIG. 1  is a diagram schematically illustrating an entire configuration of the inkjet recording device of the embodiment of the present invention. 
     The inkjet recording device of the embodiment is what is called a serial inkjet recording device that performs recording while reciprocating a print head in a main-scanning direction. As illustrated in  FIG. 1 , the inkjet recording device includes a recording device  100  and a body frame  70  supporting the recording device  100 . A guide rod  1  and a width guide  2  are extended over in the recording device  100 , and a carriage  5  is supported by the guide rod  1  and the width guide  2  so that it can move in the direction of the arrow A (main-scanning direction). The carriage  5  is connected to a timing belt  10 , and reciprocated in a main-scanning direction A when the timing belt  10  is driven by a main-scanning motor  9  and a driving pulley  28 . 
     A pressing roller  12  applies a tensile force on the timing belt  10 , which makes it possible to drive the carriage  5  without loosening of the timing belt  10 . A printing medium (recording sheet, for example)  150  is conveyed intermittently to the direction of the arrow B (sub-scanning direction) under the reciprocating carriage  5 , and ink is fired from a nozzle of a print head provided in the carriage  5  to form a given image. 
     The recording device  100  includes a cartridge  60  supplying ink and a maintenance mechanism  112  (service station) for cleaning the print head. The maintenance mechanism  112  includes a cap that covers an ink-firing port formation face (the tip of the nozzle) of the print head while the print head is not in operation, thus protecting the print head with the cap. 
     The carriage  5  is equipped with an encoder sensor therein. Scanning an encoder sheet extended in a main-scanning direction, the carriage  5  moves while detecting positions in the main-scanning direction. 
     An operating unit  104  includes various operation keys operated by an operator. A cover lock releasing button as a lock releasing unit, which is described later, is arranged on the operating unit  104 . A display unit  105  displays an operation method of the inkjet recording device or an operation state thereof, for example. Alternatively, the display unit  105  is capable of one or plural kinds of display among various display such as visual display and audio display of a message to an operator. 
     A cover  30  is provided to cover a moving area of the carriage  5  (the cover  30  is not limited to one covering only the moving area) so that an operator cannot insert his/her hand into the inkjet recording device recklessly, and is opened and closed by an operator. A cover lock unit  115  locks the cover  30  to the body housing by a cover lock member  122  (see  FIG. 5 ), so that an operator cannot open the cover  30 . 
       FIG. 2  is a block diagram illustrating a system configuration of the inkjet recording device. 
     In  FIG. 2 , a system control unit  101  includes a central processing unit (CPU), etc., and performs given operation while controlling each unit of the inkjet recording device based on a basic program for the operation of the inkjet recording device. 
     A read-only memory (ROM)  102  stores the basic program for the operation of the inkjet recording device. 
     A random-access memory (RAM)  103  stores various pieces of information unique to the inkjet recording device. 
     The operating unit  104  includes various operation keys operated by an operator. The display unit  105  displays an operation method of the inkjet recording device or an operation state thereof, or displays a message, etc., to an operator. 
     A voice output unit  106  outputs by voice a message to an operator, that is, displays the message by voice. 
     A network interface (I/F)  107  is an interface that includes an interface function for the connection to a network. 
     A carriage driving unit  108  includes a main-scanning motor  9  that drives the carriage  5  to a main-scanning direction and a driver (not illustrated) outputting signals to the main scanning motor  9 . Therefore, the main-scanning motor  9  stops the drive when the power supply to the main-scanning motor  9  or the driver is turned off. 
     A carriage driving power supplying switch  109  is turned on and off to close and open a power supplying path to the carriage driving unit  108 . When the carriage driving power supplying switch  109  is turned off, the power supplying path to the carriage driving unit  108  is opened, thus cutting off the electric power supply to the carriage driving unit  108 . 
     A power supply unit  110  supplies power input from an external commercial power supply to each unit of the inkjet recording device. 
     The print head  111  fires ink onto a recording sheet to form a given image thereon. 
     The maintenance mechanism  112  includes a cap that covers an ink-firing port formation face of the print head  111  while the print head  111  is not in operation, thus protecting the print head  111 . 
     A carriage load detecting unit  113  detects a load when the carriage  5  is moved in a main-scanning direction. When the load detected is large, the carriage load detecting unit  113  determines that some obstacle exists, and stops the movement of the carriage  5 . 
     The main-scanning position detecting unit  114  detects a position in a main-scanning direction of the print head  111 . 
     The cover lock unit  115  locks, by the cover lock member  122 , the cover  30  to the main housing so that the cover  30  cannot be opened. 
     The interlock switch  116  is a switch that is turned on and off in association with the opening and closing of the cover. When the interlock switch  116  is turned off, the power supplying path to the carriage driving unit  108  is opened, thus cutting off the power supply to the carriage driving unit  108 . 
     A timer  117  counts (measures) time of given operation. 
     A recording sheet jam detecting unit  118  detects a jam of a recording sheet moving in a sub-scanning direction. 
     An error detecting unit  119  detects that the inkjet recording device does not operate normally. 
     A cover opening/closing detecting unit  120  detects the opening and closing of the cover. 
     The system control unit  101  performs given operation while controlling each unit of the inkjet recording device. Here, the system control unit  101  as a whole may perform entire control. Alternatively, the system control unit  101  may be composed of a plurality of individual control elements to perform specific control. 
     In the description here, the system control unit  101  includes a lock control unit  101   a  for controlling the cover lock unit  115  (cover lock member  122 ), and a carriage power control unit  101   b  as a control element that performs control such as control of carriage driving power supply and other power supply, carriage driving control, control of the display unit, etc. 
     The control elements may be formed integrally with the system control unit  101 , or may be formed as separate control elements constituting the system control unit as a whole. 
       FIG. 3  is a circuit diagram illustrating a circuit for power supply to the carriage driving unit  108 . 
     The carriage driving unit  108  receives power for driving the carriage from the power supply unit  110 , as illustrate in  FIG. 3 . Here, the interlock switch  116  is a switch that is turned off when the cover  30  is opened and turned on when the cover  30  is closed. The carriage driving power supplying switch  109  is turned on and off by control of the carriage power control unit  101   b  of the system control unit  101 . Only when both of the switches  116  and  109  are turned on, the power supplying path to the carriage driving unit  108  is closed, and the power is supplied to the carriage driving unit  108 . 
       FIG. 4  is a diagram illustrating the interlock switch  116 . 
     As illustrated in  FIG. 4 , the interlock switch  116  is turned off when the cover  30  is opened, and the interlock switch  116  is turned on when the cover  30  is closed. In this manner, the interlock switch  116  is turned on and off in association with the movement of the cover  30 . 
       FIG. 5  is a diagram schematically illustrating an entire configuration of the cover lock unit  115 . 
     A hook member  123  is attached on the inner side of the cover  30 . A solenoid  121  and the lock member  122  are attached in the main housing. 
     When the cover  30  is closed, the hook member  123  is moved to a given position in the inner side of the cover  30 . Here, the hook member  123 , the solenoid  121 , and the lock member  122  are collectively referred to as the cover lock unit  115 . 
     The solenoid  121  is controlled by the lock control unit  101   a  of the system control unit  101  so as to move the lock member  122 . The lock member  122  latches the hook member  123  moved to a given position, which locks the cover  30  to the main housing, thus preventing the cover  30  from being opened. When a main power supply (not illustrated) of the inkjet recording device is turned off, the solenoid  121  moves the lock member  122  to a direction for releasing the lock, thus avoiding the cover  30  from remaining locked. 
       FIG. 6  is a flowchart illustrating control procedures by the system control unit  101  when the lock releasing unit requests the release of cover lock while the cover  30  is locked, concretely when a “cover lock releasing button” of the operating unit  104  is pushed. 
     The control procedures when the cover lock releasing button of the operating unit  104  is pushed are described with reference to  FIG. 6 . 
     When the carriage power control unit  101   b  of the system control unit  101  detects that the cover lock releasing button of the operating unit  104  is pushed (Yes at Step S 101 ), it then determines whether the printing operation is in process (Step S 102 ). If the printing operation is in process (Yes at Step S 102 ), the carriage power control unit  101   b  stops printing temporarily (Step S 103 ), and displays, on the display unit  105 , an indication prompting a user to instruct whether the printing is to be continued (Step S 104 ). Here, when the operator instructs “the printing is not to be continued” (No at Step S 105 ), the carriage power control unit  101   b  forcibly discharges a recording sheet in printing process (Step S 106 ), and moves the carriage  5  to its home position at which there is the maintenance mechanism  112  (Step S 109 ). 
     When the operator instructs “the printing is to be continued” (Yes at Step S 105 ) at Step S 105 , the carriage power control unit  101   b  restarts printing (Step S 107 ) that is stopped temporarily at Step S 103 , and moves the carriage  5  to its home position (Step S 109 ) once it confirms that the printing is finished (Yes at Step S 108 ). 
     Thereafter, the carriage power control unit  101   b  turns off the carriage driving power supplying switch  109  to open the power supplying path to the carriage driving unit  108 , and thus cutting off the power supply to the carriage driving unit  108  (Step S 110 ). After the carriage  5  stops operating, the lock control unit  101   a  releases the lock of the cover  30  by the cover lock unit  115  (Step S 111 ) so that the cover  30  can be opened, and finishes the sequence of processing. 
     If the printing operation is not in process (No at Step S 102 ) when the cover lock releasing button is pushed at Step S 102 , the carriage power control unit  101   b  immediately turns off the carriage driving power supplying switch  109  to open the power supplying path to the carriage driving unit  108 , thus cutting off the power supply to the carriage driving unit  108  (Step S 110 ). Subsequently, the lock control unit  101   a  releases the lock of the cover  30  by the cover lock unit  115  (Step S 111 ) so that the cover  30  can be opened. 
       FIG. 7  is a flowchart illustrating control procedures by the system control unit  101  after an error occurred during printing. 
     The control procedures after an error occurred during printing are as follows. 
     When an error detecting unit  119  detects that an operation error occurs (Yes at Step S 202 ) during printing (Yes at Step S 201 ), the carriage power control unit  101   b  of the system control unit  101  immediately stops the printing operation (Step S 203 ), and displays, on the display unit  105 , a message that the error has occurred (Step S 204 ). The carriage power control unit  101   b  also outputs by voice the message that the error has occurred from the voice output unit  106  (Step S 205 ). Moreover, the carriage power control unit  101   b  accesses a personal computer (PC) through a network from the network I/F  107 , and displays, on a screen of the PC, the message that the error has occurred (Step S 206 ). Then, the carriage power control unit  101   b  moves the carriage  5  to its home position (Step S 207 ). 
     Here, the main-scanning position detecting unit  114  detects whether the carriage  5  has reached its home position (Step S 208 ). Once a certain period of time has passed (Yes at Step S 209 ) without the carriage  5  reaching its home position (No at Step S 208 ), the carriage power control unit  101   b  determines that the carriage  5  is unable to move due to some obstacle such as a recording sheet. The fact that the carriage  5  is in an immovable state may be determined based on the detection of a carriage moving load by the carriage load detecting unit  113 . 
     The carriage load detecting unit  113  and the main-scanning position detecting unit  114  may be collectively referred to as an “immovability detecting unit”. 
     When the carriage power control unit  101   b  detects that the carriage  5  is unable to move, it turns off the carriage driving power supplying switch  109  to open the power supplying path to the carriage driving unit  108 , thus cutting off the power supply to the carriage driving unit  108  (Step S 210 ). Then, the lock control unit  101   a  controls the cover lock unit  115  to release the lock of the cover  30  by the cover lock unit  115  (Step S 211 ), so that the cover  30  can be opened. 
     After the cover  30  is released, the carriage power control unit  101   b  displays, on the display unit  105 , a message that the cover  30  can be opened and closed (Step S 212 ). The carriage power control unit  101   b  also outputs by voice the message that the cover  30  can be opened and closed from the voice output unit  106  (Step S 213 ). Moreover, the carriage power control unit  101   b  accesses a PC through a network from the network I/F  107  to display, on a screen of the PC, the massage that the cover  30  can be opened and closed (Step S 214 ). 
       FIG. 8  is a flowchart illustrating control procedures performed by the system control unit  101  when the main power supply is turned on. 
     The control procedures by the system control unit  101  when the main power supply is turned on are described with reference to  FIG. 8 . First, when the main power supply is turned on (Step S 301 ), the cover opening/closing detecting unit  120  detects whether the cover  30  is closed (Step S 302 ). Here, if the cover  30  is closed (Yes at Step S 302 ), the lock control unit  101   a  controls the cover lock unit  115  to lock the cover  30  in the main housing (Step S 303 ). After the cover  30  is locked, the carriage power control unit  101   b  turns on the carriage driving power supplying switch  109  to supply power to the carriage driving unit  108  (Step S 304 ), thus enabling the carriage to be driven. 
     When the cover  30  is open (No at Step S 302 ) at Step S 302 , the carriage power control unit  101   b  displays, on the display unit  105 , contents for requesting the closing of the cover so that the cover  30  is closed (Step S 305 ). The carriage power control unit  101   b  also outputs by voice contents for requesting the closing of the cover  30  from the voice output unit  106  (Step S 306 ). Moreover, the carriage power control unit  101   b  accesses a PC through a network from the network I/F  107  to display, on a screen of the PC, contents for requesting the closing of the cover  30  (Step S 307 ). 
       FIG. 9  is a flowchart illustrating control procedures by the system control unit  101  when maintenance service is provided. 
     The control procedures when maintenance service is provided are described with reference to  FIG. 9 . 
     A service person for maintenance service of the inkjet recording device cannot perform operation while the cover  30  is closed. Therefore, operation for releasing the cover  30  is necessary. Then, an operation mode exclusive for a service person is preliminarily registered in the inkjet recording device. In this manner, once operation in the operation mode exclusive for a service person is performed through the operating unit  104 , the service person can perform operation. When the input of releasing the lock for service to the operating unit  104  by the service person is detected (Yes at Step S 401 ), the lock control unit  101   a  immediately controls the cover lock unit  115  to release the lock of the cover  30  by the cover lock unit  115  (Step S 402 ). 
     In this case, the interlock switch  116  is turned off once the cover  30  is opened. Thus, the power supply to the carriage driving unit  108  is cut off, and the carriage in motion is stopped. The carriage power control unit  101   b  also temporarily stops printing. 
     In the above description, the procedures of display, etc., at Steps S 204  to S 206 , S 212  to S 214 , S 305  to S 307  are sequentially performed. However, it is obviously possible to arrange them so that only one or two of such Steps are performed. 
     As described above, in the embodiment, the lock control unit  101   a  and the carriage power control unit  101   b  of the system control unit  101  cooperate with each other to control carriage operation and the cover lock unit, which makes it possible to obtain sufficient safety in any case while preventing the carriage from moving when the cover is opened. After the cover is opened, the carriage driving power supply is not turned on unless the cover is closed and locked to the body housing. This avoids any case where a moving carriage hits a hand inserted in the device. 
     According to the embodiment, it allows an operator to safely use an inkjet recording device that is excellent in safety without a risk of injury due to the movement of the carriage because the power supply to the carriage driving unit is always set to be open every time the operator releases the cover lock to open the cover. 
     Although the invention has been described with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.