JPH04294182A - Printer - Google Patents

Abstract

PURPOSE:To provide a printer wherein printing can be performed at a constant speed regardless of speed for transmitting data and without print irregularity, which can be obtained at low cost. CONSTITUTION:A printer comprises an image memory for storing several lines of receiving data for 1 page to be printed, a transmission average time calculating means for measuring input transmission time for 1 line of the receiving data and calculating transmission average time for 1 line based on the input transmission time of a plurality of lines, and a print control means for carrying out printing with the average transmission time calculated by the transmission average time calculating means as a printing speed for 1 line.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to printers.

0002

2. Description of the Related Art In general, printers can be roughly divided into those equipped with page memory and those without. When a printer equipped with a page memory receives data to be printed, it temporarily stores one page in the page memory, reads the data from this memory, and prints the data at a constant speed. Further, in a printer without a page memory, when data to be printed is received, printing is immediately executed without waiting time.

0003

[Problems to be Solved by the Invention] The above-mentioned conventional printers without page memory print at a low speed when the data transmission speed is slow, and print at a high speed that is mechanically compatible when the data transmission speed is high. It is set to run. Therefore, the printing speed depends on the speed of input (transmitted) data. For this reason, there is a disadvantage that print quality may become uneven due to changes in printing speed. On the other hand, printers equipped with page memory do not have the above disadvantages because they print at a constant speed regardless of the data transmission speed, but they do not have the disadvantage of having a large amount of memory (capacity for at least one page). As a result, there were disadvantages such as high cost.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and provide an inexpensive printer that can print at a constant speed regardless of the data transmission speed and is free from uneven printing.

[0005]

[Means for Solving the Problems] In order to achieve this object, the present invention has the following configuration. The printer has an image memory that stores several lines of received data for one page to be printed, measures the input transmission time for one line of received data, and calculates the average time of one line transmission from the input transmission time of multiple lines. The present invention is characterized by comprising a transmission average time calculation means for calculating the average transmission time, and a printing control means for executing printing by setting the average transmission time calculated by the transmission average time calculation means to the printing speed of one line.

[0006] In a printer having such a configuration, a small-capacity memory having a storage capacity of, for example, N lines (approximately 1/several tens to several hundredths of one page) is used as the image memory. When data (eg, image data) is received, this data is stored in an image memory. One line consists of several tens to hundreds of pieces of data. Then, the data transmission time for one line stored in the image memory is stored. Once the data transmission time for a predetermined number of lines is obtained, the sum of these transmission times is divided by a predetermined number to calculate the average transmission time for one line. In addition, this average transmission time is updated sequentially by taking into account the transmission time for one line of received image data, and the printing speed for one line is also updated based on this latest average transmission time. be done. Then, when the received data stored in the image memory reaches a predetermined number of lines to start printing, the average transmission time is 1
Execute printing by setting the line printing speed.

[0007] In this way, since the transmission time of print data and the printing time are made to correspond to each other, that is, depending on the transmission speed,
Since the printing time (speed) is set for each line, uniform speed printing is possible and uneven printing can be eliminated. Image memory has a smaller capacity than page memory, which eliminates increased product costs. can.

[0008]

Embodiment FIG. 3 is a block diagram showing a specific circuit configuration of a printer according to the present invention.

Image data to be printed is stored in the image memory 2 via the I/O port 5. ROM(
A read-only memory (read-only memory) 3 stores a control program for a CPU (central processing unit) 1, which will be described later, and a RAM (random access memory) 4 is a memory for exchanging various data in the course of various calculations. Further, the control circuit 6 controls the driving of the thermal head 7 that performs printing and the motor (head feeding and paper feeding motor) 8 under the control of the CPU 1. As shown in FIG. 4, the image memory 2 has N
A small-capacity memory is used that stores data for a line, that is, several tens to several hundredths of one page. Said C
PU1 has the function of measuring the input transmission time (t) of one line of received image data (one line consists of several tens to hundreds of data), and the function of measuring the input transmission time (t) of one line of image data from the sum of the transmission times of multiple lines. It has a transmission average time calculation function that calculates the average time (T). Also, it is determined whether the image memory 2 has stored a predetermined number of lines (M lines), and M
It has a printing speed setting function that executes printing by setting the average transmission time (T) of the number of M lines to the printing speed of one line when the number of lines reaches the number of lines. In the embodiment, M lines are set to a number equal to or smaller than N. In other words, (N
-M) The line image memory is for absorbing variations in data transmission time.

FIG. 1 is a flowchart showing specific processing operations of the printer of the embodiment. When data to be printed (image data) is received [step (hereinafter referred to as ST) 1], in ST2 it is determined whether the received data is image data. Assuming that the received data is command data other than a print command, the determination in ST2 is NO, and in ST11, processing according to the command is executed. If the received data is image data (data to be printed), the determination in ST2 is YES, and the received data is stored in the image memory 2 (ST3). ST
In step 4, it is determined whether or not storage of one line of data has been completed. Assuming that one line of data has been stored, the determination in ST4 is YES. Above ST2
When it is determined that the data is image data, a timer is activated at the same time and measures the storage time for one line, that is, the transmission input time for one line. Therefore, when one line of data has been stored, the transmission time for one line (
t) is obtained and stored (ST5). Then, the average transmission time (T) of one line is calculated (ST6). In this case, since the image data has only been imported once, (
t) is assumed to be (T). Then, 1 is added to n (n indicating the number of times image data has been captured). Since n is initially "0", n is now set to "1" (ST7
). In ST8, it is determined whether n is M (predetermined number of lines). Therefore, the storage of data in the image memory 2 is repeated until n becomes M, that is, until M lines are stored, and each time n increases, the average transmission time (T) is calculated in ST6. Suppose that M lines of data are stored in the image memory 2. For example, if 12 lines are stored in the image memory 2 (M=12, n=1).
2) At this point, the average transmission time (T) of the transmission times for 12 lines is calculated in ST6. Therefore, ST
8 becomes YES, and the printing routine is started (ST9
), and n is set to "0" (ST10). At this time, a time equal to the average transmission time (T) is set to the printing speed for one line.

FIG. 2 is a flowchart showing specific processing operations of the printing routine. When the printing routine starts, the driving of the thermal head 7 and motor 8 is controlled,
Print processing is executed (ST21). One line is printed corresponding to the average transmission time (T), and when printing for one line is completed, the printer waits for (T) time (ST22). This processing operation is executed repeatedly.

[0012] In this way, since the transmission time of print data and the printing time are made to correspond to each other, that is, depending on the transmission speed,
Since the printing time (speed) is set for each line, uniform speed printing is possible and uneven printing can be eliminated. Image memory has a smaller capacity than page memory, which eliminates increased product costs. can.

[0013] In the embodiment, an example is shown in which the received data is image data, but character codes can also be used. Further, in the embodiment, an example of a parallel head type printer is shown, but even in a printer using a serial head, printing quality can be improved by moving the head at a constant speed.

[0014]

Effects of the Invention As described above, the present invention includes an image memory that stores several lines of print data for one page to be printed, and an image memory that measures the input transmission time for one line of print data to be transmitted. , a transmission average time calculation means that calculates the average transmission time of one line from the input transmission time of a plurality of lines, and a printing control that executes printing by setting the average transmission time calculated by the transmission average time calculation means at the printing speed of one line. Since the transmission time of the print data and the printing time are made to correspond, and the printing time (speed) for each line is set according to the transmission speed, uniform speed printing is possible and printing unevenness is prevented. The image memory has a smaller capacity than the page memory, and has an excellent effect of achieving the purpose of the invention, such as eliminating the increase in product costs.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing processing operations of an embodiment printer.

FIG. 2 is a flowchart showing a printing routine of the embodiment printer.

FIG. 3 is a block diagram showing the circuit configuration of the embodiment printer.

FIG. 4 is an explanatory diagram showing an image memory of the embodiment printer.

[Explanation of symbols]

1 CPU 2 Image memory

Claims (1)

[Claims] 1. An image memory that stores several lines of received data for one page to be printed, and an image memory that measures the input transmission time for one line of received data, and calculates the transmission time of one line from the input transmission time of multiple lines. A printer comprising a transmission average time calculation means for calculating an average time, and a print control means for executing printing by setting the average transmission time calculated by the transmission average time calculation means to the printing speed of one line.