1. A printer adapted to be connected to a host computer and to receive data including control commands from the host computer, the printer comprising:
a receive buffer that temporarily stores received data;
a data interpreter that interprets the data in said receive buffer;
a controller responsive to said data interpreter that controls said printer;
a state detector that detects whether said printer is in a first state in which data is received and the received data is not printed, or a second state in which data is received and the received data is printed;
a clearing unit that clears said receive buffer, the clearing unit being adapted to automatically clear said received buffer after said state detector detects said first state; and
a data discarding unit that discards print data received from said host computer while said printer is in said first state.
2. The printer of claim 1, further comprising:
a setting unit that sets a data handling mode that determines how data are handled when said printer is in said first state; and
a reading unit that reads said data handling mode in response to said printer entering said first state as determined by said state detector;
wherein said clearing unit is further adapted to clear said receive buffer only when said data handling mode is set to allow clearing of said receive buffer.
3. The printer of claim 2, wherein said setting unit is adapted to set said data handling mode in response to a specific control command from said host computer.
4. The printer of claim 1, wherein said data discarding unit is adapted to not discard real-time commands received from said host computer while said printer is in said first state.
5. The printer of claim 1, wherein said data discarding unit is further adapted to discard data only when said data handling mode is set to allow discarding the data received from said host computer.
6. The printer of claim 1, further comprising a print buffer for storing expanded print data, wherein said clearing unit is further adapted to clear both said receive buffer and said print buffer.
7. The printer of claim 1 wherein said first state is an off-line state in which said data interpreter does not interpret received print data and does interpret received command data, and said second state is an on-line state in which said data interpreter interprets all received data.
8. A method of controlling a printer, comprising the steps of:
(a) detecting whether said printer is in a first state in which data is received and the received data is not printed or in a second state in which data is received and the received data is printed;
(b) automatically clearing a receive buffer, for temporarily storing received data, after said printer enters said first state; and
(e) discarding print data received from a host computer after said receive buffer is cleared in step (b) and until said second state is detected in step (a).
9. The method of claim 8, wherein step (b) is accomplished immediately after said first state is detected in step (a).
10. The method of claim 9, further comprising the steps of:
(c) setting a data handling mode so as to either allow or not allow clearing of said receive buffer; and
(d) reading said data handling mode in response to detection of said first state in step (a);
wherein step (b) comprises clearing said receive buffer only when said data handling mode read in step (d) allows clearing of said receive buffer.
11. The method of claim 10, wherein step (c) is accomplished according to a specific control command from said host computer.
12. The method of claim 8, wherein step (c) further comprises not discarding real-time command data after said receive buffer is cleared in step (b) and until said second state is detected in step (a).
13. The method of claim 10, wherein step (e) comprises discarding data only when said data handling mode read in step (d) further allows discarding the data received from said host computer.
14. The method of claim 8, further comprising a step of:
(f) saving in said receive buffer data received from said host computer after said receive buffer is cleared in step (b) and until step (a) detects the second state, instead of performing step (e).
15. The method of claim 8, further comprising a step of:
(g) clearing said receive buffer when said second state is detected in step (a) after said first state had been detected previously.
16. The method of claim 8, wherein step (b) comprises clearing said receive buffer and a print buffer.
17. The method of claim 15, wherein the printer further comprises a print buffer, and step (g) further comprises clearing said print buffer.
18. The method of claim 8, wherein said first state is an off-line state and said second state is an on-line state.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for manufacturing an ultraviolet light-emitting device in which a p-type semiconductor is used,
wherein, in case of making crystal growth by supplying at least three types of crystal raw materials in a pulsed manner, said p-type semiconductor is prepared by supplying a p-type impurity raw material both at the same time when or after starting supply of at least two of at least three types of crystal raw materials, and before starting supply of the other type of crystal raw material than said at least two types of crystal raw materials in one cycle during which all the said at least three types of crystal raw materials are supplied once each, and
wherein the at least two of the at least three types of crystal raw materials are supplied simultaneously or at least in a partially time-overlapped manner.
2. The method for manufacturing an ultraviolet light-emitting device as claimed in claim 1, wherein said at least two types of crystal raw materials are the group III elements, and said other types of crystal raw materials are the group V elements.
3. A method for manufacturing an ultraviolet light-emitting device in which a p-type semiconductor is used,
wherein, in case of making crystal growth by supplying plural of types of crystal raw materials in a pulsed manner, said p-type semiconductor is prepared by supplying a p-type impurity raw material both at the same time when or after starting supply of predetermined types of crystal raw materials, and before starting supply of other types of crystal raw materials than said predetermined types of crystal raw materials in one cycle during which all the types of crystal raw materials of said plural types of crystal raw materials are supplied once each, with said predetermined types of crystal raw materials being the group III elements and said other types of crystal raw materials being the group V elements,
wherein said group III elements are Al and Ga, and said group V element is N, supply of Al and Ga and supply of N are carried out alternately in a pulsed manner, with Al and Ga being supplied simultaneously or at least in a partially time-overlapped manner, and said p-type impurity raw material is Mg and supplied only during the supply of Al and Ga or after starting of supply of Al and Ga and before starting of supply of N.
4. The method for manufacturing an ultraviolet light-emitting device as claimed in claim 3, wherein the ratio of Al to AlGaN is not less and 20%.
5. The method of manufacturing an ultraviolet light-emitting device as claimed in claim 3, wherein the ratio of Al is between 30% and 60%.
6. A method for manufacturing a p-type semiconductor used in an ultraviolet light-emitting device, wherein said p-type semiconductor is prepared by repeating:
a desired number of times for a cycle consisting of:
a first step wherein supply of TMGa, TMAl, and Cp2Mg is commenced at a first timing, and supply of Cp2Mg is finished at a second timing at which supply of Cp2Mg which has been continued for a predetermined period of time was completed during the supply of TMGa and TMAl;
a second step wherein supply of TESi is commenced immediately after or after the second timing at which supply of Cp2Mg is finished during the supply of TMGa and TMAl, and supply of TMGa, TMAl, and TESi is finished at a third timing at which supply of TESi which has been continued for a predetermined period of time is completed; and
a third step wherein supply of NH3 is commenced immediately after or after the third timing at which supply of TMGa, TMAl, and TESi is completed, and supply of NH3 is finished at a fourth timing at which supply of NH3 which has been continued for a predetermined period of time is completed.
7. The method as claimed in claim 6, wherein a small amount of N is continuously supplied in case of preparing said p-type semiconductor.
8. A method for manufacturing an ultraviolet light-emitting device in which a p-type semiconductor is used, wherein, in case of making crystal growth by supplying plural types of crystal raw materials in a pulsed manner,
wherein said p-type semiconductor being composed of AlGaN prepared by laminating both a first crystal layer formed from Ga and Al which are supplied simultaneously or at least in a partially time-overlapped manner, and a second crystal layer formed from N, and wherein said first crystal layer formed from Ga and Al is doped with Mg and Si for their respective adjacent periods of time and Mg and Si is placed closely in said crystal layer formed from Ga and Al at a predetermined ratio.
9. The method for manufacturing an ultraviolet light-emitting device as claimed in claim 8, wherein said second crystal layer is not doped with impurities.