Access to printing material container

Abstract

The present invention provides a storage device that enables identification data to be readily rewritten and ensures normal completion of a data writing operation in a short time period. In the storage device of the invention, an ID comparator determines whether or not identification data transmitted from a host computer coincides with identification data stored in a memory array. In the case of coincidence, the ID comparator sends an access enable signal EN to an operation code decoder. The operation code decoder analyzes a write/read command, switches over a direction of data transfer with regard to the memory array based on a result of the analysis, and requires an I/O controller to change a high impedance setting of a signal line connecting with a data terminal DT. This series of processing allows access to an address in the memory array specified by a count on an address counter.

1 . A storage system comprising a plurality of printing material containers and a control unit, each printing material container having a non-volatile storage device that connects with a clock signal line, a data signal line, and a reset signal line via a bus and a reservoir unit that keeps a printing material therein, said control unit connecting with said storage device included in said printing material container via the clock signal line, the data signal line, and the reset signal line said control unit comprising: 
 a clock signal generation circuit that generates a clock signal;    a reset signal generation circuit that generates a reset signal for initializing said storage device;    an identification information output circuit that outputs identification information to identify a storage device included in a desired printing material container among said plurality of printing material containers; and    a data output circuit that transmits a data array including the output identification information and a write/read command to the data signal line synchronously with the clock signal,    said storage device included in said each printing material container comprising: a data bus that connects with the data signal line;    a storage element that has a storage area sequentially accessed;    a comparator that connects with the data bus and compares the identification information output from said control unit with identification information stored in the storage element to determine coincidence or incoincidence of the two pieces of identification information;    an input-output controller that is interposed between the storage element and the data bus and controls a direction of data transfer with regard to the storage element as well as a direction of data transfer with regard to the data bus; and    a command decoder that connects with the data bus and the comparator, analyzes the write/read command input via the data bus when a result of the determination by the comparator represents coincidence of the identification information output from said control unit with the identification information stored in the storage element, and requires the input-output controller to switch over the direction of data transfer with regard to the data bus based on a result of the analysis.    
     
     
         2 . A storage system in accordance with  claim 1 , wherein said storage device included in said each printing material container further comprises: 
 an address counter that increments a count thereon synchronously with the clock signal input via the clock signal line to specify a position in the storage area of the storage element to be accessed, and resets the count to an initial value at a time of initialization,    wherein the input-output controller sets the direction of data transfer with regard to the storage element to a reading direction and prohibits data transfer with regard to the data bus as initial settings, and maintains the initial settings until the command decoder completes the analysis of the write/read command.    
     
     
         3 . A storage system in accordance with  claim 1 , wherein said control unit causes the reset signal generation circuit to output the reset signal to the reset signal line, and 
 said control unit causes the data output circuit to transmit the data array including the identification information, which is assigned to said storage device included in said desired printing material container to be accessed, and the write/read command to the data signal line synchronously with the clock signal, so as to gain access to said storage device in said desired printing material container.    
     
     
         4 . A storage system in accordance with  claim 3 , wherein said storage device included in each said printing material container causes the address counter to reset the count thereon to the initial value in response to detection of the reset signal, 
 said storage device causes the comparator to compare the identification information transmitted to the data bus with the identification information stored in the storage element to determine coincidence or incoincidence of the two pieces of identification information, and    when the result of the determination by the comparator represents coincidence of the identification information transmitted to the data bus with the identification information stored in the storage element, said storage device causes the command decoder to analyze the write/read command transmitted to the data bus, controls the data transfer with regard to the data bus and the data transfer with regard to the storage element based on the result of the analysis, and carries out either one of an operation of writing data at a desired position in the storage element and an operation of reading data from the storage element.    
     
     
         5 . A storage system in accordance with  claim 4 , wherein the identification information output circuit of said control unit outputs common identification information common to all said storage devices, and 
 the comparator of each storage device stores the common identification information therein.    
     
     
         6 . A storage system in accordance with any one of  claims 1  to  5 , wherein said control unit further comprises a power supply compensation circuit that gives compensational power supply for a predetermined time period after cutoff of general power supply, 
 the reset signal generation circuit included in said control unit generates the reset signal on at least either one of an occasion of starting power supply to said control unit and an occasion of cutoff of the power supply, and    in response to detection of the reset signal during a writing operation of data, the data output circuit included in said control unit immediately terminates transmission of the data and instantly transmits preferential data to be completely written in the predetermined time period when the power supply compensation circuit gives the compensational power supply.    
     
     
         7 . A storage system in accordance with any one of  claims 1  to  5 , wherein the clock signal generation circuit included in said control unit lengthens a cycle of the clock signal in the case of output of a write command via the data output circuit than a cycle in the case of output of a read command.  
     
     
         8 . A storage system in accordance with any one of  claims 1  to  5 , said storage system further comprising: 
 a module substrate that has said plurality of storage devices mounted thereon and a storage device detection signal line laid thereon to give cascade connection with each storage device and have one grounded end and the other end connecting with said control unit,    wherein said control unit further comprises a storage device detection circuit that determines whether or not all said storage devices are properly mounted on the module substrate, based on a value of the storage device detection signal line.    
     
     
         9 . A storage system in accordance with  claim 8 , wherein the storage device detection circuit included in said control unit determines that all said storage devices are mounted properly on the module substrate when the storage device detection signal line shows a ground voltage.  
     
     
         10 . A storage system in accordance with  claim 8 , wherein the storage device detection circuit included in said control unit determines that at least one storage device is not properly mounted on the module substrate when the storage device detection signal line shows a voltage other than a ground voltage.  
     
     
         11 . A storage system in accordance with any one of  claims 1  to  5 , wherein said storage device stores a diversity of data regarding a type of the printing material accommodated in said each printing material container.  
     
     
         12 . A storage system in accordance with any one of  claims 1  to  5 , wherein power supply to each storage device is allowed only when said control unit carries out a writing/reading operation of data into and from said storage device.  
     
     
         13 . A storage system in accordance with  claim 1 , wherein the storage element included in said each storage device has a specific section between a head position and a predetermined position of the storage area, the specific section being subjected to a writing operation under a predetermined condition and otherwise storing the identification information in an unrewritable manner.  
     
     
         14 . A storage system in accordance with  claim 1 , wherein the clock signal line, the data signal line, and the reset signal line are included in a flexible cable.  
     
     
         15 . A method of processing an access requirement in a storage device attached to a printing material container, said printing material container having a storage device that includes a storage element, which has a storage area sequentially accessed and a specific section between a head position and a predetermined position of the storage area to store identification information therein, said storage device sharing a clock bus that is connected to a clock signal line, a data bus that is connected to a data signal line, and a reset bus that is connected to a reset signal line with a storage device included in another printing material container, 
 said method comprising the steps of:    resetting a count on an address counter to an initial value in response to detection of a reset signal on the reset bus;    comparing identification information transmitted to the data bus with the identification information stored in the storage element to determine coincidence or incoincidence of the two pieces of identification information;    when the result of the determination represents coincidence of the identification information transmitted to the data bus with the identification information stored in the storage element, analyzing a write/read command transmitted to the data bus;    controlling data transfer with regard to the data bus and data transfer with regard to the storage element based on the result of the analysis; and    carrying out either one of an operation of writing data at a desired position in the storage element and an operation of reading data from the storage element, based on the count on the address counter.    
     
     
         16 . In a printing material container having a non-volatile storage device, which includes a storage element sequentially accessed, a method of storing identification information in a specific section located between a head position and a predetermined position of a storage area in the storage element, 
 said method comprising the steps of:    carrying out retrieval to find a piece of identification information that coincides with the identification information stored in the storage element of said storage device;    when the piece of identification information that coincides with the identification information stored in the storage element is found, transmitting the piece of identification information and a write command to said storage device;    transmitting a data array to said storage device, the data array including the identification information after data corresponding to an end position of the storage area in the storage element of said storage device; and    writing data up to the end position of the storage area in the storage element and subsequently writing the identification information from the head position to the predetermined position of the storage area in the storage element, according to a count on an address counter.    
     
     
         17 . A method in accordance with any one of claims  15  and  16 , said method being applied to a set of at least two printing material containers, each having said storage device that stores a different piece of identification information.