JP3480417B2 - Print data distribution system and printing device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print data distribution system and a printing device.

[0002]

2. Description of the Related Art As is well known, a general computer is configured so that various electronic data can be easily exchanged via a portable recording medium such as a floppy disk or MO, the Internet or a LAN. .

[0003]

As described above, since the computer is configured to easily exchange electronic data, it is desirable to limit the number of uses due to the print data distributed for a fee and the copyright. There was a problem that print data could be printed any number of times.

Therefore, an object of the present invention is to provide a print data distribution system that can distribute print data with a limited number of times of use, and a printing apparatus that can be used to configure such a print data distribution system. , To provide.

[0005]

In order to solve the above problems, a print data distribution system and a printing apparatus according to the present invention are provided.
Is configured as follows.

[0006]

[0007]

[0008]

[0009]

The print data distribution system according to the present invention is
Using the given public key, the print data is data that is to be printed in the printing apparatus, and a data ID that is identification information of the print data.
The print data supply device includes an encrypted print data generation unit that generates encrypted print data, which is data including a usage count designation value indicating the number of times the print data is permitted to be used.

Further, the print data distribution system performs communication on the paper according to the communication means for communicating with the device connected through the first communication medium and the supplied data of the predetermined format. An information storage unit that stores a printing unit, a public key, and a secret key for decrypting information encrypted using the public key, and a storage unit for storing a correspondence relationship between a data ID and a designated number of times of use. Request response means for returning the public key stored in the information storage means to the sender of the public key provision request by using the communication means when the public key provision request is received by the utilization status information storage means and the communication means , And when the encrypted print data is received by the communication means, the usage status information storage means is in a first state in which the data ID included in the encrypted print data is not stored, or the usage status is In the second state where the data storage device stores the data ID included in the encrypted print data, and a value of "1" or more is stored as the number-of-uses designation value related to the data ID, If it is in the second state, the received encrypted print data is decrypted using the secret key stored in the information storage means, and the predetermined result is determined based on the decryption result. Format data is generated and supplied to the printing unit, and a print control / number change process is executed to subtract “1” from the number-of-use designation value in the use status information storage unit.
If the status is in the state, the data ID and the usage count designating value included in the received encrypted print data are stored in the usage status information storage means, and then the print control / frequency change processing is executed, An encrypted print data processing means for discarding the received encrypted print data when the status is in the state,
And a printing device having a normal print data processing means for generating data of a predetermined format based on the print data and supplying the print data to the printing means when the normal print data is received by the communication means.

That is, the printing device included in this print data distribution system has a function of outputting the public key corresponding to the private key held by itself, but does not have the function of outputting the private key. Then, the print data supply device generates encrypted print data that can be decrypted only by the printing device that has the private key corresponding to the public key, based on the given public key. In addition, the encrypted print data generated by the print data supply device includes the data ID and the use count designation value.

Then, in the printing apparatus, when the encrypted print data relating to a certain print data is first received, the data ID and the usage count designation value included in the encrypted print data are used as the usage status information storage means. Memorized in. After that, each time the encrypted print data is printed, the usage count designation value is decreased by "1", and the usage count designation value becomes "0". Unable to perform (state determined by the encrypted print data processing means to be neither the first nor the second state)
Is formed.

Thus, print data distribution according to the present invention
The system is a system that can distribute print data (data for distribution) with a limited number of uses.

When constructing this print data distribution system, a host computer connected to the printing apparatus is set as an element of the system, and an encrypted print data generating means of the print data supply apparatus is provided via the second communication medium. And received the public key from the host computer,
It is desirable to employ means for generating encrypted print data and transmitting the generated encrypted print data to the host computer via the second communication medium. By configuring the print data distribution system in this way, print data can be distributed at high speed. When configuring the print data distribution system as described above, the second communication medium may be the same as or different from the first communication medium. In other words, the printing device may function as a local printer of the host computer, and the printing device may be a network printer connected to a network to which the host computer and the print data distribution device are connected. .

[0016]

The printing apparatus according to the present invention includes a communication unit for communicating with a device connected via a communication medium, and a printing unit for printing on paper according to the supplied data of a predetermined format. An information storage unit that stores a public key and a secret key for decrypting information encrypted using the public key, and a data ID included in the encrypted print data received by the communication unit. When a public key provision request is received by the communication means, the utilization status information storage means for storing the designated number of times of use in association with each other is used to inform the sender of the public key provision request using the communication means. Request response means for returning the public key stored in the storage means, and data I included in the encrypted print data in the usage status information storage means when the encrypted print data is received by the communication means. Is stored in the first state, or the data ID included in the encrypted print data is stored in the usage status information storage unit, and “1” or more is used as the number-of-uses designation value related to the data ID. It is determined whether the value of is stored in the second state or in any other state. If it is in the second state, the received encrypted print data is stored in the information storage means. The data ID included in the received encrypted print data is generated by using the private key that has been decrypted to generate data in a predetermined format based on the decryption result and supplying the data to the printing unit.
Corresponding to the print control / number of times changing process of subtracting “1” from the number of times of use specified value in the use status information storage means,
In the case of the first state, after the data ID and the designated number of times of use included in the received encrypted print data are stored in the utilization status information storage means, the print control / number of times changing process is executed, When the normal print data is received by the communication unit and the encrypted print data processing unit that discards the received encrypted print data, when the normal print data is received, the predetermined format based on the print data is received. A normal print data processing unit that generates data and supplies the data to the printing unit.

[0018] With these printing devices, the ability to configure the print data distribution system of the present invention described above.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings.

<First Embodiment> First, an outline of a print data distribution system according to a first embodiment of the present invention will be described with reference to FIG.

As schematically shown in FIG. 1, the print data distribution system according to the first embodiment includes a printing device 10.
And a host computer 40 connected to the printing apparatus 10 and a data distribution center 50 (print data supply apparatus). The data distribution center 50 is a computer that includes a magnetic card writer and that functions as a use count limited medium creating unit and a distribution data creating unit. The data distribution center 50 holds several kinds of print data for distribution. Data distribution center 50
The print data for each arrangement stored in the
Is a print data in a special format (a format that cannot be printed by a normal printing device) prepared for distribution to other users, and at the beginning of the layout print data, there is information indicating that the print data is distribution print data. , And a data ID indicating the type of itself (print data for distribution). More specifically, the layout print data used in the present embodiment has information indicating that it is print data for distribution and data ID indicating the type of itself (print data for distribution), The normal print data is DES-encrypted data using a predetermined key, which is continued, and the printing device 10 stores the predetermined key.

Further, the data distribution center 50 has a function of generating a use count restriction card 55 (use count restriction medium) and a distribution data recording medium 56. The use count limit card 55 is a magnetic card in which data IDs relating to some distribution print data and a use count specification value that defines the number of times each print data can be used for printing are recorded. The distribution data recording medium 56 is the number-of-uses limit card 5
5 is a recording medium (flexible disk in this embodiment) in which a file of each print data for distribution in which a data ID is recorded is recorded. Note that the use limit card 55 and the distribution data recording medium 56 are requested by the user to create a distribution print data type (data ID) by email or mail. When received, it is created and distributed to the user by mail.

The host computer 40 is a computer having a general configuration, and prints the contents of the print data file for distribution recorded in the distribution data recording medium 56 to the printing apparatus 1.
0 (Provides print data file for distribution to printer 1
Copy to port 0). A printer driver or the like for the printing apparatus 10 is also installed in the host computer 40, and the host computer 40 is also used to create normal print data and supply it to the printing apparatus 10.

The printing device 10 is a device capable of printing distribution print data and normal print data. However, the printing device 10 is a device that refers to / updates the information recorded in the number-of-uses limit card 55 when printing the distribution print data.
A magnetic card reader / writer 17 (medium reading / writing means) to which 5 is mounted is provided.

Specifically, as shown in FIG. 2, the printing device 10 comprises a magnetic card reader / writer 17, a control panel 18, a printing mechanism 19 and a control section 20.
The magnetic card reader / writer 17 is a device for reading and rewriting the information stored in the usage count defining card 55. The control panel 18 is an interface between the user and the printer 10, and is composed of a plurality of buttons for operating the printer 10, several LEDs for displaying the operating state of the printer 10, and a liquid crystal panel. ing. The printing mechanism 19 is a mechanism that functions as a printing unit, and actually prints on paper. The printing apparatus 10 is a so-called laser beam printer, and the printing mechanism 19 includes a paper feeding device, a paper transporting mechanism, a toner cassette, a print engine, and the like.

The control unit 20 includes a host interface circuit 21, a CPU 22, a RAM 23, and an EEPROM (electri).
A cally erasable and programmable ROM 24, a memory control unit 25, a ROM 26, and an interface circuit unit 27.

The host interface circuit 21 is a circuit for receiving normal print data and distribution print data transmitted by the host computer 40. The ROM 26 is a memory that stores programs and fonts. CPU2
Reference numeral 2 denotes a control circuit that controls each unit in the control unit 20,
It functions as a distribution data processing unit and a normal print data processing unit in cooperation with other units. This CPU 22 is R
The program stored in the OM 26 is read onto the RAM 23, and the program operates according to the read program. Also,
At that time, the CPU 22 uses the RAM 23 to temporarily store the data received by the host interface circuit 21 and the data generated by itself based on the data. The EEPROM 24 is used for the printing device 10.
It is a non-volatile memory used for storing data that defines the default operating conditions of.

The memory control unit 25, in accordance with an instruction from the CPU 22, transfers data from the host interface circuit 21 to the RAM 23.
To transfer data to and from the RAM 23 to the printing mechanism 1
The process of transferring data to the print engine in 9 is performed. In the interface circuit unit 27, the CPU 22 allows the magnetic card reader / writer 17, the control panel 18, and
It consists of several interface circuits for exchanging information with the transport mechanism and the like in the printing mechanism 19. That is,
The CPU 22 accesses the use count limiting card 55 set in the magnetic card reader / writer 17 via the interface circuit unit 27. In addition, the CPU 22
Recognizes the state of each button in the control panel 18 (whether or not each button is pressed) via the interface circuit unit 27, and L in the control panel 18 is recognized.
Controls the ED and liquid crystal panel. Further, the CPU 22
Through the interface circuit section 27, the states of various mechanisms in the printing mechanism 19 (the amount of remaining toner in the toner cassette, the presence or absence of paper jam, etc.) are recognized and controlled.

The operation and usage of the printing apparatus 10 will be described below with reference to FIG.

The user of the printing apparatus 10 prints any distribution print data recorded in the distribution data recording medium 56 (or a copy of the distribution print data generated in the host computer 40). In this case, the number-of-uses limit card 55 is set in the magnetic card reader / writer 17 of the printing device 10. Then, by operating the keyboard or the like of the host computer 40, the host computer 40 is caused to transmit desired distribution print data to the printing apparatus 10.

On the other hand, as shown in FIG. 3, when the printer 10 (CPU 22) is activated, it waits for data to be received by the host interface circuit 21 (step S101; NO). . Then, when the data starts to be received (step S101; YE
S), the CPU 22 determines whether the received data is normal print data or distribution print data, based on the data included at the beginning of the data that has been received by the host interface circuit 21 ((S). Step S102). Then, when the data is normal print data (step S102; NO), the CPU 22 performs a process according to the content of the print data and supplies the print data to the printing mechanism 19 (print engine) (step S10).
3). That is, when the print data is described in a high-level language, the CPU 22 interprets the content of the print data to generate an intermediate code, expands the generated intermediate code into image data, and supplies the image data to the printing mechanism 19. To do. If the print data is image data, the CPU 22
The processing of supplying the printing mechanism 19 to the printing mechanism 19 is performed as it is. Then, the CPU 22 returns to step S101 and waits for the data to be received by the host interface circuit 21.

When the data received by the host interface circuit 21 is the distribution print data (step S102; YES), that is, the information indicating the distribution print data and the data ID are provided at the beginning thereof. If the data includes the data, the CPU 22 determines whether or not the usage count limit card 55 is attached to the magnetic card reader / writer 17 (step S104). When the number-of-uses limiting card 55 is not attached to the magnetic card reader / writer 17 (step S104; N
O), the CPU 22 is the host interface circuit 21.
Nothing is done to the data received by (the data is discarded and the data reception is interrupted), and the process returns to step S101.

When the number-of-uses limiting card 55 is attached to the magnetic card reader / writer 17 (step S10)
4; YES), the CPU 22 reads the number-of-uses designation value related to the data ID (hereinafter, referred to as processing target data ID) included in the received distribution print data from the number-of-uses limitation card 55, and It is determined whether or not the value exceeds "0" (step S105). When the usage count specification value related to the processing target data ID is not stored in the usage count restriction card 55, and the processing target data I stored in the usage count restriction card 55
When the designated number of times of use regarding D is "0" (step S105; NO), the CPU 22 does nothing with respect to the data received by the host interface circuit 21, and returns to step S101.

When the designated number of times of use for the data ID to be processed exceeds "0" (step S105; YE)
S), the CPU 22 performs processing for distribution print data on the received data (distribution print data) (D).
The ES encryption is decrypted to obtain normal print data, and the print data is subjected to necessary processing and supplied to the printing mechanism 19 (step S106). Then the CPU 22
Controls the magnetic card reader / writer 17 so that the processing target data ID in the usage-restricted card 55
The designated value of the number of times of use is decremented by "1" (step S107). After that, the CPU 22 executes step S
Returning to 101, the host interface circuit 21 waits for data to be received.

That is, the printing device 10 included in the print data distribution system according to the first embodiment has a function of printing distribution print data that cannot be printed by a normal printing device. When the print data for distribution is supplied from the host computer 40, the printing device 10
The distribution print data is printed using the above function only when the usage count specification value for the distribution print data stored in the usage count limit card 55 is “1” or more. Further, when printing the distribution print data, the printing apparatus 10 performs a process of decrementing the corresponding usage count designation value in the usage count limit card 55 by “1”.

Since the printing apparatus 10 operates in this manner, the print data distribution system according to the present invention can distribute print data with a limited number of times of use.

<Second Embodiment> FIG. 4 shows the arrangement of a print data distribution system according to the second embodiment of the present invention.

As shown in the figure, the print data distribution system according to the second embodiment includes a printing device 12 and a printing device 12.
And a data distribution center 52 (print data supply device) connected to the host computer 42 via the Internet. Although only one printing device 12 is shown in FIG. 4, this print data distribution system is usually
It is operated in a form including a plurality of printers 12 and a plurality of host computers 42 connected to them.

The printing device 12 included in the print data distribution system has substantially the same hardware configuration as the printing device 10 in the first embodiment. However, the printing device 12
Is a device that does not include the magnetic card reader / writer 17. In addition, the EEPROM 2 in the printing device 12
The number 4 is also used to store the public key, the secret key, and the number-of-uses management table 35. That is, in this embodiment, the EEPROM 24 functions as an information storage unit and a usage status storage unit. Although details of the public key and the secret key and the number-of-uses management table 35 will be described later, the printing device 10 stores the number-of-uses management table 35 in which no public key and secret key are stored in the EEPROM 24. Shipped as it exists.

The configurations and operations of the data distribution center 52 and the host computer 42 will be described below with reference to FIG.

As shown, the data distribution center 52
Like the data distribution center 50, each holds a plurality of types of print data for distribution to be distributed to buyers of the printing device 12. However, the distribution print data held by the data distribution center 52 is print data that can be printed by a normal printing device.

The data distribution center 52 is a Web
It is a base file server (a computer having the functions of a WWW server and an FTP server),
When receiving an introduction information request of a predetermined content from each host computer 42, the introduction information indicating what kind of distribution print data is prepared is returned to the sender of the request.

Further, when the data distribution center 52 receives a data distribution request including the data ID which is the identification information of the distribution print data and the public key from each host computer 42, the data distribution center 52 uses the public key and the data concerned. The encrypted print data of the print data for distribution specified by the ID is generated and returned to the sender of the data delivery request. In the data distribution center 52 of this embodiment, encrypted print data is generated by the following procedure, and the host computer 42
Will be returned to.

First, DES (data encryption standar)
A key for encryption according to d) (hereinafter, referred to as a DES key) is arbitrarily generated. Then, by using the DES key, the data ID included in the data distribution request, the number of times of use designation value that is predetermined according to the data ID, and the distribution print data designated by the data ID are calculated. DES-encrypted data of the following data is generated. That is, by decoding, the data ID, the designated number of times of use,
DES-encrypted data for obtaining distribution print data is generated. Next, at the head of the generated DES encrypted data, data type information indicating that it is encrypted print data, the public key included in the data distribution request, and the encryption of the DES key with the public key The encrypted key data is added to create encrypted print data, which is returned to the host computer 42.

The data distribution request program 45 installed in the host computer 42 is a program (HTML data and applet) executed on the Web browser. This data distribution request program 45
The host computer 42 on which is executed executes the following processing in response to a user's instruction.

When an operation for instructing the output of the key issuance request is made, the host computer 42 sends a key issuance request having a predetermined content to the printer 12. Then, the host computer 42 internally stores the data (public key) returned by the printing device 12 in response to the key issuance request as a public key to be incorporated in the data delivery request.

When a predetermined operation is performed, the host computer 42 acquires the introduction information from the data distribution center 52 and displays a screen (Web page) for selecting distribution print data based on the acquired introduction information. To display. Then, when the distribution print data on the screen is selected by the user, the host computer 42 determines the data ID of the selected distribution print data.
And a data delivery request including the stored public key are transmitted to the data distribution center 52. Then, as a response to the data delivery request, the data delivery center 52
The encrypted print data sent from will be saved as a file. Further, when another predetermined operation is performed, the host computer 42 supplies the encrypted print data that has been converted into a file to the printing device 12 (the encrypted print data file is connected by the printing device 12). Copying to the specified print port) is performed.

The operation of the printer 12 will be described below in association with the operation of the host computer 42 with reference to the flow charts shown in FIGS. 6 and 7.

The user of the printing apparatus 12 first causes the host computer 42 to execute the data distribution request program 45, and instructs the host computer 42 (data distribution request program 45) to output a key issuance request.
Upon receiving this instruction, the host computer 42 transmits the key issuance request to the printing device 12, as already described.

As shown in FIG. 6, the printer 12 (CP
U22), when activated, waits for data to be received by the host interface circuit 21 (step S201; NO). Then, when the data is received (step S201; YES) and the data is a key issuance request (step S202; YES), C
The PU 22 first determines whether the public key and the secret key are stored in the EEPROM 24 (step S2).
11).

When the public key and the secret key are not stored in the EEPROM 24 (step S211; YE
S) In other words, when the printing device 12 is in the state at the time of shipment, the CPU 22 generates a private key and a public key of the RSA public key system (step S212). The procedure for generating the private key and public key in step S212 is as follows.
This is the same as that generally performed when using the RSA public key system. That is, in this step, two large prime numbers are randomly generated, and a public key and a secret key are generated from those prime numbers.

Next, the CPU 22 stores the generated public key and secret key in the EEPROM 24 (step S21).
3) Then, control is performed to return the public key stored in the EEPROM 24 (in this case, the public key generated in the previous step) to the host computer 42 (step S214). And CPU22 is step S2.
Returning to 01, the host interface circuit 21 waits for data reception.

When the public key and the secret key are stored in the EEPROM 24 (step S211; YES), C
In step S214, the PU 22 does not newly generate the public key and the secret key, but uses the public key stored in the EEPROM 24 (in this case, the public key generated in response to the key generation request received in the past). Control for returning to the host computer 42 is performed. And CPU
22 returns to step S201 and waits for reception of data by the host interface circuit 21.

The printing apparatus 1 is controlled by step S214.
The data (public key) sent from No. 2 is stored as a public key to be included in the data delivery request by the host computer 42 that issued the key issuing request.

After the public key is prepared in the host computer 42 by instructing the output of the key issuance request, the user can perform a predetermined operation on the host computer 42 to select distribution print data. Is displayed on the display of the host computer 42, and distribution print data to be downloaded is selected. By selecting the print data for distribution, a data delivery request including the data ID of the print data for distribution and the stored public key is transmitted to the data distribution center 52, and a file holding the encrypted print data is created. , Host computer 42
Generated within. Then, the user causes the host computer 42 to supply the encrypted print data in the file to the printing device 12 by performing a predetermined operation.

When the data received by the host interface circuit 21 is not a key issuance request, the CPU 22 in the printer 12 has a key issuing request (step S202;
If NO, that is, if it is normal print data or encrypted print data, the operation as the print data processing means is started. Then, the CPU 22 determines whether the received data is normal print data or encrypted print data, based on the data included at the beginning of the data that has been received by the host interface circuit 21 (step S1). S203). When the received data is normal print data (step S203; N
O), the CPU 22 processes the print data according to the content and supplies the print data to the print mechanism 19 (print engine) (step S204). That is, when the print data is described in a high-level language, a process of interpreting the content of the print data to generate an intermediate code, expanding the generated intermediate code into image data, and supplying the image data to the printing mechanism 19 is performed. . If the print data is image data,
The processing of supplying the printing mechanism 19 to the printing mechanism 19 is performed as it is. Then, the CPU 22 returns to step S201 and waits for the data to be received by the host interface circuit 21.

On the other hand, when the data received by the host interface circuit 21 is the encrypted print data (step S203; YES), the CPU 22
The public key included in the encrypted print data is EEPR
It is determined whether or not it is stored in the OM 24 (FIG. 7:
Step S221). When the public key and the private key are not stored in the EEPROM 24, or the EEPR
When the public key stored in the OM 24 does not match the public key in the encrypted print data (step S221;
NO), the CPU 22 is the host interface circuit 2
Nothing is done to the data received by 1 (the data is discarded and the data reception is interrupted), and the process returns to step S201.

If the public key stored in the EEPROM 24 and the public key in the encrypted print data match (step S221; YES), the CPU 22 causes the EEPROM
A part of the encrypted print data (the head part of the DES encrypted data) is decrypted by using the secret key stored in 24 to obtain the data ID and the use count designation value (step S222). That is, the CPU 22 decrypts the encrypted key data (the DES key encrypted with the public key) subsequent to the public key in the encrypted print data with the private key to obtain the DES key. obtain. Then
The CPU 22 uses the DES key to decrypt a part of the DES encrypted data (data ID, designated number of times of use and distribution print data encrypted with the DES key) that follows the encrypted key data. By doing so, the data ID and the designated number of times of use are acquired.

The CPU 22 then acquires the acquired data I
It is determined whether D is stored (registered) in the usage count management table 35 (step S223). When the acquired data ID is not stored in the usage count management table 35 (step S223; NO), the data ID acquired in step S222 and the usage count specification value are
It is stored (registered) in the usage count management table 35 in the EEPROM (step S224). Then CPU2
2 uses the private key stored in the EEPROM 24 to decrypt the remaining data, performs the necessary processing on the decryption result (normal print data), and supplies the decrypted result to the printing mechanism 19 (step S226). Then, the CPU 22 causes the EEP
After decrementing the number-of-uses designation value in the number-of-uses management table 35 on the ROM 24 by "1" (step S227), the process returns to step S201.

On the other hand, if the acquired data ID is stored in the usage count management table 35 (step S22)
(3; YES), the CPU 22 determines whether or not the use count designation value acquired in step S222 exceeds “0” (step S225). When the designated number of times of use is "0" (step S225; NO),
The CPU 22 does nothing with respect to the data received by the host interface circuit 21 (discards the data and interrupts the data reception), and proceeds to step S
Return to 201 (FIG. 6). When the designated number of times of use exceeds "0" (step S225; YES), the CPU 22
Performs the processing from step S226 already described.

As described above in detail, the printing device 12 included in the print data distribution system according to this embodiment.
Has a function of outputting a public key corresponding to the private key held by itself, but does not have a function of outputting a private key. Then, the data distribution center 52 generates, based on the given public key, encrypted print data that can be decrypted only by the printing device 12 having the private key corresponding to the public key. In addition, the encrypted print data generated by the data distribution center 52 includes a use count designation value.

When the printing device 12 first receives encrypted print data relating to certain distribution print data, the printing device 12 uses the data ID included in the encrypted print data and the use count designation value as the use count. It is stored in the management table 35. After that, each time the distribution print data is printed, the usage count designation value is decreased by "1", and the distribution print data is supplied with the usage count designation value being "0". If it does (step S225: NO), the process for the data ends without printing.

Since the printing device 12 operates in this manner, the print data distribution system according to the present invention can distribute print data with the number of times of use limited.

The print data distribution system according to the first embodiment is a system in which the print data for distribution can be printed by using any printing device 10 as long as the number-of-uses limit card 55 is provided. In the print data distribution system according to the second embodiment, a certain encrypted print data is generated only by the printing device 12 that has generated the public key included in the data delivery request that triggered the generation of the encrypted print data.
It is a printing system. That is, according to the print data distribution system of the second embodiment, the print data can be distributed from the data distribution center 52 to the host computer 42 in a form in which the number of times of use and the printing device 12 to be used are limited.

<Modifications> The print data distribution system according to each embodiment can be modified in various ways. For example, in the print data distribution system according to the first embodiment, from the data distribution center 50 to the host computer 40,
Although the print data for distribution is distributed by the flexible disk, the print data for distribution may be distributed by communication. On the contrary, the print data distribution system according to the second embodiment is the host computer 4
Although the data is exchanged between the device 2 and the data distribution center 52 by communication, the data may be exchanged between these devices by a floppy disk or the like.

Further, the printing apparatus 12 according to the second embodiment.
The function of generating the private key and the public key is added to make the confidentiality of the private key higher (if the configuration of the second embodiment is adopted, the manufacturer of the printing apparatus 12 also has the private key). Because there is no way to know.) Therefore, without providing this function, the EEPROM 24 and the R
The private key and the public key may be written and stored in the OM 26.

Further, the printing device 12 is constructed so that the private key and the public key are not regenerated (the process is branched depending on the presence or absence of the key in step S211). When managing and limiting the number of distribution print data downloadable by a user in the data distribution center 50 based on the number of public keys transmitted from the user, the maximum number of private keys and public keys is N.
It can be generated twice (a maximum of N sets of private keys and public keys are stored in the EEPROM 24), and a private key corresponding to the public key included in the received encrypted print data is selected and decrypted. Alternatively, the printing device 12 may be modified. In the printing apparatus 12 according to the second embodiment, the reason why the public key is returned when the key is stored in the EEPROM 24 is that all the computers connected to the printing apparatus 12 have the printing apparatus 12 This is so that the encrypted print data printing function can be used (the data distribution request can be sent to the data distribution center 50 by executing the data distribution request program 45).

Further, the printer 12 may be configured so that the public key and the private key are generated and the public key is printed by operating the control panel 18. However, since the public key is data with a large size,
As in the embodiment, it is desirable that the public key be input to the host computer 40 by communication.

Further, in the print data distribution system according to the second embodiment, the distribution print data is not directly encrypted by the public key because the DES encryption is more effective than the public key encryption. Because it can be done at high speed. Therefore, if the processing speed may be slow,
The distribution print data may be directly encrypted by the public key, and the encrypted print data may be directly decrypted by the private key. Further, encrypted print data in which only a part (for example, the first part) of the print data for one page is encrypted by the public key and the remaining part is the normal print data is generated. As described above, the data distribution center 52 may be configured, and the printing device 12 may be configured to be able to decrypt such encrypted print data. However, in the case of such a configuration, printing cannot be performed by another printing apparatus, but some data in the encrypted print data remains as data that can be processed. Moreover, it is desirable to configure the system so that the entire distribution print data is encrypted in some form.

[0070]

According to the print data distribution system of the present invention, print data can be distributed with a limited number of uses.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a print data distribution system according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a printing apparatus included in the print data distribution system according to the first embodiment.

FIG. 3 is a flowchart showing an operation procedure of a printing apparatus included in the print data distribution system according to the first embodiment.

FIG. 4 is a configuration diagram of a print data distribution system according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram of the overall operation of the print data distribution system according to the second embodiment.

FIG. 6 is a flowchart showing an operation procedure of a printing apparatus included in the print data distribution system according to the second embodiment.

FIG. 7 is a flowchart showing an operation procedure of a printing apparatus included in the print data distribution system according to the second embodiment.

[Explanation of symbols]

10, 12 printing device 18 Control panel 19 Printing mechanism 20 Control unit 21 Host interface circuit 22 CPU 23 RAM 24 EEPROM 25 Memory controller 26 ROM 27 Interface circuit 30 toner cassette 40, 42 Host computer 35 Usage count management table 45 Data distribution request program 50, 52 Data distribution center 55 Restricted usage number card (magnetic card) 56 Distribution data recording medium (flexible disk)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI H04N 1/44 B41J 29/00 Z (58) Fields investigated (Int.Cl. ⁷ , DB name) G06F 3/12 B41J 29 / 00 B41J 29/38 G06F 13/00 540 G06F 17/60 142 H04N 1/44

Claims (3)

(57) [Claims] 1. A print data distribution system including a printing device and a print data supply device, wherein the print data supply device uses the given public key to perform printing in the printing device. Data ID that is the encrypted data of the print data and is the identification information of the print data
And an encrypted print data generating unit that generates encrypted print data that is data including a usage count designating value that indicates the number of times the print data is permitted to be used, and the printing apparatus includes a first communication medium. Communication means for communicating with a device connected via a device, a printing means for printing on paper according to the supplied data of a predetermined format, a public key, and an encryption using the public key. An information storage unit that stores a secret key for decrypting the encrypted information, a usage status information storage unit that stores a correspondence relationship between a data ID and a designated number of times of use, and a public key provision request by the communication unit. When received, the request response means for returning the public key stored in the information storage means to the sender of the public key provision request using the communication means, and When the encrypted print data is received, it is in the first state in which the data ID included in the encrypted print data is not stored in the usage status information storage means, or the encryption is stored in the usage status information storage means. The data ID included in the encrypted print data is stored, and
If it is in the second state in which a value of "1" or more is stored as the designated number of times of use relating to the data ID or in any other state, and if it is in the second state, reception is performed. The encrypted print data is decrypted by using the secret key stored in the information storage unit, the data of the predetermined format is generated based on the decryption result, and the data is supplied to the printing unit, and the usage status information is also supplied. When the print control / number-of-times changing process of subtracting “1” from the number-of-uses designated value in the storage unit is executed, and in the first state, the data ID included in the received encrypted print data and the number of uses After storing the designated value and the usage status information storage means,
When the print control / number-of-times changing process is executed and the status is other than those, the encrypted print data processing unit that discards the received encrypted print data, and the normal print data is transmitted by the communication unit. A print data distribution system comprising: a normal print data processing unit which, when received, generates the data in the predetermined format based on the print data and supplies the data to the printing unit. 2. A host computer connected to the printing device, further comprising: an encrypted print data generation unit of the print data supply device receiving the public key from the host computer via a second communication medium. when the print data distribution system according to claim 1, wherein the generating the encrypted print data, and transmits the generated encrypted print data to the host computer via the second communication medium. 3. A communication means for communicating with a device connected via a communication medium, a printing means for printing on paper according to the supplied data of a predetermined format, and a public key. An information storage unit that stores a secret key for decrypting the information encrypted using the public key, a data ID included in the encrypted print data received by the communication unit, and a usage count designation value And a usage status information storage unit for storing the information and a storage unit for storing the information in the sender of the public key provision request using the communication unit when the public key provision request is received by the communication unit. Request response means for returning the public key stored in the means, and when the encrypted print data is received by the communication means, the encrypted print data is included in the usage status information storage means. First of that data ID is not stored
Or the data ID included in the encrypted print data is stored in the usage status information storage means,
In addition, it is determined whether the second state in which a value of "1" or more is stored as the number-of-uses designated value related to the data ID or the other states, and when the second state is present, Decrypting the received encrypted print data using the secret key stored in the information storage means, generating data of the predetermined format based on the decryption result, supplying the data to the printing means, and receiving In the first state, the print control / number-of-times changing process for subtracting “1” from the number-of-uses designation value in the utilization status information storage unit corresponding to the data ID included in the encrypted print data is executed. In this case, after storing the data ID included in the received encrypted print data and the designated number of times of use in the utilization status information storage means, the print control / number of times changing process is executed, and other conditions are stored. If there is, the encrypted print data processing means for discarding the received encrypted print data, and when the normal print data is received by the communication means, the data of the predetermined format based on the print data And a normal print data processing means for generating and supplying the generated print data to the printing means.