JPH02258368A - Medium control method in printer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates primarily to media control in inkjet printers. [Prior art J] Printer ink adheres to the medium and then completely dries.
The time required for fixing varies depending on the printing method, ink, medium, environment, etc., but in particular, inkjet methods, which spray ink particles onto the medium, require a longer drying time than other methods. - Shooting-wise, it cannot withstand the friction of the printing surface immediately after printing. Further, in a printer using a single cylindrical platen, a medium presser is provided that presses the medium against the platen near the printing position in order to bring the medium into close contact with the platen and to correct the direction in which the medium travels. In view of the above-mentioned problem of friction on the printing surface, the position of this medium presser is usually located below the printing position. Therefore, in a printer where ink is slow to dry, such as an inkjet type printer, if the medium is reversed immediately after printing, the undried ink will be rubbed by the medium presser and the printing surface will be smeared. In conventional technology, in order to avoid the above-mentioned ink rubbing, reverse feeding of the medium is completely prohibited, or means is provided to allow backward feeding of the medium only for the distance between the printing position and the medium presser. . [Problems to be Solved by the Invention] In the conventional technology, by setting the position of the medium pusher approximately one line away from the printing position, it is possible to reverse feed the medium by a certain amount for printing superscript characters, etc. Ta. However, all long reverse feeds were considered to pose a risk of ink rubbing and were prohibited. As a result, the following three cases where reversal can be done safely were ignored: In other words, ■ A long line feed in the forward direction is performed after printing, and the last printed line does not return to the media holder even if you reverse feed. ■ The media in the part of the last printed line has already been cut off. - A certain amount of time has passed since the last print, and the ink has already dried on the printing surface. This may remove the continuous form medium from the tractor bin, for example, by interrupting use of the continuous form medium, reversing the medium, retracting its leading edge into the push-type tractor, and disconnecting the tractor from the drive force. It has not been possible to provide an inkjet type printer with a function such as continuous form evacuation, which allows the use of other media without causing problems. [Means for Solving the Problems] In order to solve the above-mentioned problems, the medium control method of the present invention includes a print storage means for storing whether or not printing has been performed after inserting a new medium, and a counter means for counting the number of motor drive steps from the latest printing line on the medium to the medium holding position; and an elapsed time since the last printing was performed on the medium. and time comparison means for comparing the output of the timer means with a predetermined time constant. [Function] According to the above configuration, it is possible to more accurately determine whether there is a risk of ink rubbing when reverse feeding of the medium is required, and the above-mentioned temporary evacuation of the continuous form medium is also possible under certain conditions. becomes. [Example] An example of the present invention will be described below with reference to the drawings. In this embodiment, reverse paper feeding in an inkjet printer will be explained. FIG. 1 shows a block diagram of an embodiment of the present invention. Further, FIG. 2 shows a model diagram of this embodiment. The line feed motor drive means 2 is a conventional step motor drive means that rotates the line feed motor in response to commands from the medium control means 1. The counter means 3 is means for holding the number of motor drive steps from the final printing position to the medium pressing position. It is initialized by a signal indicating that printing has been performed, such as a print head drive signal or a print start signal. The initial value at this time is the number of motor steps (indicated by a in FIG. 2) from the medium pressing position to the lower end of the printing position. The counter means 3 switches the function of addition and subtraction according to the rotation direction signal of the line feed motor sent from the medium control means 1, and performs addition and subtraction according to the rotation step signal of the line feed motor also sent from the medium control means 1. At this time, forward feeding of the medium corresponds to addition, and backward feeding corresponds to subtraction. That is, the counter means 3 holds the motor drive step from the last printed line to the medium presser, and outputs this to the medium control means l. The print storage means 4 is a 1-bit register, and when the printer returns from the no-medium state to the medium-inserted state,
Alternatively, it is initialized when there is a designation from the medium control means 1. The initial value indicates "no printing", but changes to the state indicating "printing" by inputting a head energization signal. The medium detecting means 5 is a photo ink printer consisting of a set of a light emitting part and a light receiving part, and as shown in FIG.
one is provided, and the opposite one is provided in a groove cut in the platen. This type of installation is possible because this printer is an inkjet printer and does not necessarily require that the back side of the medium be supported by a platen. This position is b steps from the medium presser below the printing position. The medium detection means 5 detects the presence or absence of a medium at this position and notifies it to the medium control means l. This paper bale holds down the media by means of a disk, shown as a circle in FIG. This disk has gear-shaped protrusions formed around it and presses the medium with light point contact, so ink rubbing does not occur.This disk is provided at several locations, and the medium detection means 5 is located between them. The timer means 6 is initialized to 0 by a signal indicating that printing has been performed, such as a print head drive signal or a print start signal. Thereafter, it continues to measure time in an appropriate unit until the next initialization, and continues to output time data to the time comparison means 7. That is, the timer means 6 holds and outputs the elapsed time since the last printing. The maximum value and unit for time measurement are determined with consideration given to preventing overflow from occurring in practice. The time comparison means 7 compares the output of the timer means 6 with predetermined time data, and outputs a signal indicating the magnitude relationship between them to the medium control means 1. Here, this predetermined time data is the time required for the ink used for printing to dry, and is set to a sufficiently long value so that no problems occur in practical use. The medium control means 1 determines whether or not reverse line feed is possible based on the information from each means described above, and also controls each means8.
The flowchart is shown in FIG. During normal printing, when performing a line feed in the forward direction, the medium control means 1 transmits the direction of rotation and the number of steps to the counter means 3 before rotating the line feed motor in the forward direction, and then the line feed motor driving means 2 executes the line feed. let On the other hand, before reversing the medium, the output of the print storage means 4 is first referred to. When it is in the "not printed" state, the direction of rotation and the number of steps are transmitted to the counter means 3, and reverse feeding is executed as it is. When in the "printed state", the cumulative amount of media feeding output by the counter means 3 is compared with the amount of reverse feeding to be performed from now on,
Determine whether the last printed line returns below the position of the media presser by reverse feeding. When it stops above the medium presser, the direction and amount of rotation are transmitted to the counter means 3, and the line feed motor driving means 2 is caused to execute the line feed. When returning to the lower side of the medium presser, first, the output of the time comparing means 7 is referred to, and it is checked whether the drying time of the printing surface has already elapsed. If the drying time has been exceeded, the direction and amount of rotation are transmitted to the counter means 3, and reverse feeding is executed. If the drying time has not yet ended, the medium is forwarded or reversed from the position of the final printed line given by the output of the counter means 3 to the position of the medium detection means 5, and the medium at the position of the final printed line is already separated. Check to see if there are any. At this time as well, the direction and amount of one rotation are transmitted to the counter means 3. When there is no medium, that part has already been separated, so the medium feed amount for detection is subtracted from the specified reverse feed amount and the direction and amount of one rotation is transmitted to the counter means 3.
Execute reverse feed. If a medium is present, there is a risk of ink rubbing and reverse feeding must be disabled, so the medium sent for detection is returned to its original position and the process ends. During the above operations, the printer will be in a state where there is no media,
The next time a medium is inserted, the counter means 3 and print storage means 4 are initialized. [Effect of the invention J] As described above, there are three conditions in which the medium can be safely reversed, namely: ■ A long line feed in the forward direction is performed after printing, and even if the medium is reversed, the last printed line is The media has not returned to the media holder. ■ The media in the last printed line has already been cut. ■ A certain amount of time has passed since the last print, and the ink has already dried on the printing surface. can be detected by the present invention. In particular, by being able to detect ■, it is now possible to support the above-mentioned evacuation function for continuous form media, provided that it is executed after the continuous form medium is cut off at the bottom edge of the printed page. Become. It can be said that this condition should naturally be met before the form saving operation, and it can be said that the effects of the present invention are great. FIG. 3 is a flowchart of the medium control means 4. Applicant: Seiko Epson Co., Ltd. Agent Patent attorney: Kisabe Suzuki (1 other person)

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention. FIG. 2 is a model diagram of the printing position section of the printer according to the embodiment of the present invention.

Claims (2)

[Claims] (1) In a printer equipped with a medium presser that presses the medium against the platen near the lower side of the inking position from the print head to the medium, a print storage means for storing whether printing has been performed after inserting a new medium. a medium detecting means located at the rear along the medium traveling direction; and a counter means for counting the number of motor drive steps from the latest printed line on the medium to the medium holding position. Method. (2) It includes a timer means for outputting the elapsed time since the last printing on the medium, and a time comparison means for comparing the output of the timer means with a predetermined time constant. The medium control method according to claim 1, characterized in that: