1. Field of the Invention
The present invention relates to a printer for printing bit images according to data input from an external data processor such as a host computer, and more particularly, to a printer of this type comprising display means for displaying the operation state thereof in detail.
2. Description of Related Art
In a printer system comprising a printer and a data processor such as a host computer, an image reader, which are connected to each other, the printer processes data sent from the data processor, for example, the printer converts them into dot images or bit map images to be actually printed out according to a font pattern stored in a font memory. After completing the data process of, for example, one page, the printer starts to print the converted images on a sheet of printing paper.
On an operation panel of the printer, generally, there is provided a lamp for indicating a state of data process, for example, such a state that the data are being received from the external data processor, in addition to a lamp for indicating that the printer is in a waiting state for the printing operation. If the operator can confirm that the data are being received from the external data processor, he may feel easy. Furthermore, after all the data have been received therefrom, the operator may wish to set the data processor in an off-line state so as to use another function of the data processor, or he may wish to turn off the printer system. In those cases, the operator can enter a proper instruction to the printer system by judging the state of data process according to the lamp provided on the operation panel.
On the other hand, in the printer, various kinds of processes are executed as follows. Upon receiving data sent from the external data processor, for example, data having a relatively short length may be received at a relatively long time interval, and a large amount of data composed of many pages may be received. Further, program data of page description language such as post script may be received in addition to character code data and bit image data. Furthermore, in the data process of the printer, there are a character code process for converting character code data into bit image data according to a font pattern stored in the font memory and storing them in a bit map memory, a graphic image process for storing bit image data in the bit map memory, and a page description language process for converting data into graphic image data according to a program of the page description language and storing them in the bit map memory. Respective times required for receiving individual data and respective times required for processing individual data are different from each other over a wide range.
If the operator can not grasp the operation state of the printer such as a data receiving state, a data processing state, a waiting state, he may be anxious about the operation of the printer. For example, he may suppose that he uselessly waits for completion of the data process for a long time after the data process is suspended due to an error. Furthermore, he may judge by mistake that the data process is completed, and thereafter, he may do misoperation.
In a conventional printer, there is provided a lamp which flickers while receiving or processing data and lights until a sheet of printing paper is discharged to a paper discharging tray. In the printer of this type, the operator can not distinguish the data receiving state from the data processing state, and therefore, we can not judge a timing for setting the data processor in the off-line state or a timing for turning off the printer system until the data process is completed.
In another conventional printer, there is provided a lamp which flickers while receiving data, lights out when a trouble is caused therein and lights in the other cases. In the printer of this type, the operator can grasp the data receiving state, however, he can not grasp whether or not the data process is completed until a sheet of printing paper is discharged after printing out.
Therefore, in the printer, there is preferably provided a lamp for indicating the operation state of the printer so that the operator can judge that the printer is operating normally.