JPH07100387B2 - Printer - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a printer having an improved printing method after paper end detection.

[Prior art]

2. Description of the Related Art Conventionally, a printer that prints according to input data while feeding paper line by line is equipped with a suction unit for paper sheets and a paper feed mechanism. Further, such a printer is provided with a paper end detector that detects the end of the paper. This paper-end detector is usually disposed on the paper feed side, which is before the print position in the feed direction, for convenience of mounting. Therefore, the print position when the signal is output by the paper end detector is located considerably above the end of the paper. Therefore, if printing is disabled when the above signal is detected, the margin below the paper becomes too large. In order to prevent this, after the above signal is detected, it is possible to print up to the range where a predetermined number of line feeds that can be mechanically printed are made, and then the paper end signal (hereinafter referred to as "PE signal") .)
Is output and at the same time, the printing is disabled.

[Problems to be Solved by the Invention]

However, after the detection signal is output by the paper end detector, the print limit is managed by the instructed paper feed amount thereafter. Therefore, when the platen knob is turned in the forward feed direction by the operator after the above signal is output, the print limit of the actual paper moves in the forward feed direction, but the print limit for management does not change, Even when there is no more paper at the print position, the printable area is considered and printing is continued. Further, even when the paper is pulled out by the operator, the printing is actually continued up to the print limit position in management although the paper does not exist at the print position. Therefore, there is a problem that the surface of the platen is directly printed on the platen, and the surface of the platen is stained with ink, or the platen or the print head is damaged. Further, there is a problem that the received data is erased without being visually displayed due to blank hitting.

[Object of the Invention]

The present invention has been made to solve the above problems, and an object of the present invention is to make a print-disabled state when a predetermined condition is satisfied after the end of a sheet is detected. This prevents the printing operation when there is no paper.

[Means for solving problems]

The configuration of the invention for solving the above problems is a paper feed mechanism that feeds a paper to a print position, and a paper end detector that is disposed on the paper feed side of the print position and that detects the end of the paper. A printer having a print control device that continues printing for a predetermined number of lines according to input data when the end of the paper is detected by the paper end detector. After the end detector detects the trailing edge of the paper, when the data to be printed is not input within a predetermined time, the printing is disabled.

[Action]

The printer normally prints the data that has been input so far when a predetermined number of characters of data is input or when a print command code is input. When the end of the paper is detected by the paper end detector, printing can be performed by the specified paper feed amount after that, but if the input data is not input within the specified time, the printing is disabled. . When the printing operation stops near the end of the paper, the operator may misunderstand that the printing operation of the paper is completed and may rotate the platen knob or pull out the paper. Then, when the data is not input for the predetermined time, it can be considered that the continuous printing operation of the printer is stopped.After that, the paper is in the unprintable state, so even if the paper is removed during the stop, it is empty. Hitting can be prevented.

【Example】

The present invention will be described below based on specific examples. First
In the figure, reference numeral 1 is a central processing unit (CPU) which constitutes a control device of the printer. The CPU 1 is connected to a host computer 14 via an input / output interface 13, and inputs non-character symbol system codes such as character symbol system codes and function codes from the host computer 14. ROM2, ROM3, and input / output interfaces 4, 5 and 6 are connected to the CPU 1 via an address bus, a data bus and a control bus, respectively. The ROM 2 stores a print control program including various function processing routines and a 24 × 24 dot font. Further, the RAM 3 is provided with an area for temporarily storing an input code group, a line buffer for creating a print pattern for two lines, and the like. I / O interface 4,5,
Drive units 7, 8 and 9 are connected to 6 respectively, and each drive unit has an LF motor 10 for feeding paper and a CR motor 1 for moving a carriage having a print head.
1, the print solenoid 12 that drives the impact wire,
Each is connected. And, they are based on the dot pattern formed in the line buffer and the functional processing by the command input from the host computer.
Driven by. FIG. 4 is a sectional view showing a printing mechanism and a paper feeding mechanism of the printer. 20 is the platen, which is the platen axis
It is rotated by the LF motor 10 via 21. Below the platen 20, a paper guide 22 having a semicircular cross section and extending in the platen shaft 21 direction is arranged. The paver guide 22 is provided with a first pressure roller 23 and a second pressure roller 24. Further, 25 is a print head having an impact wire, and the print solenoid 12
Driven by. 27 is a guide for guiding the continuous form. The paper 30 is guided along the paper guide 22, is pressed by the first pressure roller 23, the second pressure roller and the platen 20 and is guided along the circumferential surface of the platen 20, and the print head 25 and the platen 20. It passes through the gap of and is held by the paper bail 26. A paper end detector 15 for detecting the end of the paper is provided in the paper guide 22 on the paper feeding side B with respect to the printing position A. The paper end detector 15 outputs a detection signal according to the presence or absence of reflected light, and has a function of detecting the presence of the paper 30. 2 and 3 are flowcharts showing the processing procedure of the CPU 1. The printer of this embodiment is designed to receive data and create an output image by utilizing the idle time during printing, so that the process of FIG. 2 is performed during the idle time of the print process of FIG. Are processed in parallel. The output line buffer is provided with an A buffer and a B buffer,
When the contents of one buffer are being output and the other buffer is empty, the next output image is created in that buffer. First, when the device is powered on, the host computer
The connection procedure with 14 is executed, and the printer and the host computer are connected (100). Next, the paper end detector 15 initializes a counter L that counts the feed amount of the paper after the end of the paper is detected to 0, and resets a flag FLG that is set when the paper end is detected ( 102). (A) Processing before paper end detection One character of data is received from the host computer (10
4) The FLG status is judged (106), but since the FLG is off, the routine proceeds to step 124, where a predetermined number of characters have been entered in the input buffer, or a print command code such as LF, FF, CR, Is determined (124, 126). By such processing, data is accumulated in the input buffer, and when the buffer becomes full or a print command code is given, the corresponding font is read next and output image data is created. To create the image data, a free buffer is searched (128, 134) and the free line buffer is created (130, 136). Also, the respective buffer flags are set to indicate that the image data has been created (132, 138). When both buffers are not empty, the CPU is released from this process for a certain period of time, and then the empty buffer is searched again (140). The print processing program is controlled so that the contents of the A buffer and the B buffer are printed alternately in this order. When the A buffer is full (200), the contents of the buffer are printed (202) and after the printing is completed, the buffer flag is reset (204) so that the buffer can be written. When the buffer flag is reset, an output image can be created in the buffer according to the received data by the program of FIG. If the buffer is not full, the CPU is released from this process, and after a certain period of time, the state is determined again (201). Depending on the next commanded line feed number, the paper feed amount is LF counter LFC.
Is set to (206). Normally, step 208-
By the loop of 216 and 208, the 1-pitch feed command is output (210), the LFC is decremented by 1 (212), and when the LFC becomes 0, the feeding of the paper is completed, the process returns to step 220, and the above-mentioned is performed. Similarly to the above, the state of the B buffer is determined, and the printing process of the content is performed (220 to 224). In this way, printing is performed by alternately switching the buffers A and B. (B) Processing after paper end detection When the paper end is detected during the paper feeding operation described above, the flag FLG is set (216, 218), and after one pitch feed, the FLG state is judged. If YES (214), the paper feed amount after the paper end is detected is counted by the counter L (228). Then, the feed amount is compared with a predetermined value LS, and printing can be performed while the feed amount is smaller than LS. However, when the paper feed amount after detecting the paper end becomes LS or more, the paper end signal (PE signal), the device abnormality signal (FAULT signal), and the BUSY signal are output to the host computer 14, and the paper end is set. Is processed to generate an alarm for (232). As a result, after the paper end is detected, it is not possible to print over a certain amount of paper feed. When the paper is set in the printer and goes online, the printing process is continued. On the other hand, when the paper end detector 15 detects the paper end, the flag FLG is set.
In the illustrated program, when both the A buffer and the B buffer are empty, that is, when the printer is in a state where the mechanical printing operation is stopped, the determination in step 106 is Y for the first time.
Become ES. In this case, the process branches to step 108, but the determination in step 108 is unconditionally NO for the first time.
Is set so that the subtraction timer is set to a predetermined time each time step 112 is passed. After that, as described above, one character is received each time step 104 is passed, and the reception time interval of the data is monitored in step 108, and the next data is not input even if a predetermined time elapses. If so, the determination in step 108 is YES. Similar to the process of step 232 described above, PE signal, FAU
The LT signal and the BUSY signal are output, processing such as offline is performed, and thereafter, the printing is disabled until the paper is set and the online status is obtained (110). In this way, when the mechanical operation of the printer is stopped after the paper end is detected and data is not received within a certain period of time, it is considered that the printer processing has ended, and There is.

【The invention's effect】

As described above, the present invention is characterized in that after the end of the paper is detected by the paper end detector, the printing is disabled when no data is received within a predetermined time. Therefore, even if the printing position is near the end of the paper and the printer accidentally performs operations such as pulling out and sequentially feeding the paper while the printer is at rest, the printer according to the present invention is in a state in which printing cannot be performed, and therefore blank printing is not performed. To be prevented.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of a printer according to a specific embodiment of the present invention, and FIGS. 2 and 3 are flow charts showing a processing procedure of a CPU used in the printer. , FIG. 4 is a sectional view showing a paper feeding mechanism of the printer. 15 …… Paper end detector, 20 …… Platen, 22 ……
Paper guides, 23, 24 ... Pressure rollers, 25 ...
… Print head, 30… Paper

Claims (1)

[Claims] 1. A paper feed mechanism for feeding a paper to a print position, a paper end detector disposed on the paper feed side of the print position for detecting the end of the paper, and a paper end detector for detecting the paper end. When a trailing edge of the paper is detected, a printer having a print control device that continues printing for a predetermined number of lines according to the input data, and the print control device detects that the trailing edge of the paper is detected by the paper end detector. After being detected, when the data to be printed is not input within a predetermined time, the printer is set to the unprintable state.