JPS59103775A - Paper feed controller - Google Patents

Abstract

PURPOSE:To enable to reduce irregularity in feeding of a recording paper, by a method wherein the period of time from the moment of completing printing in a line to the moment of outputting a starting signal for printing in the next line is measured, and the timing of generating a step pulse is varied in accordance with the measured value. CONSTITUTION:When the current printing action is finished and preparation for the next printing is completed, a printing ready signal 13 is outputted from a printing controller 11, and when printing data are prepared, a printing starting signal 14 is generated, the controller 11 causes the signal 13 to rise in response to the signal 14, and the period of time X required for this process is measured by a timer circuit 15. When the period of time X exceeds a predetermined value alpha according to the printing condition of the printer, a long period detection signal 16 is inputted into a motor pulse generating circuit 17. The circuit 17 generates a motor pulse 26 in accordance with the signal 14 when the period of time X is shorter than the predetermined value alpha, and generates the pulse 26 in accordance with the signal 16 when the period of time X is longer than the value alpha. Accordingly, the movement interval of the recording paper is maintained to be constant by the printing timing, and irregularity in feeding can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a paper feed control device for recording paper used in a printer that performs recording while moving the recording paper line by line.

For example, facsimile machines usually receive image signals obtained by line sequential scanning line by line. Therefore, the printer used in such an apparatus records information line by line while moving the recording paper line by line in the sub-scanning direction. In order to move the recording paper stepwise in this manner, a step motor is used as a driving source for conveying the recording paper. When the step motor is driven, a conveyance roller rotates via a transmission mechanism such as a belt, and the recording paper is conveyed.

(Prior Art) By the way, the paper feed control device used in conventional printers, when printing of one line is finished and a signal to start printing operation of the next line is output, starts sending a step pulse at a predetermined timing. It was generated and supplied to the step motor. That is, simple paper feeding is performed in which the recording paper is moved one line in the sub-scanning direction each time.

FIG. 1 shows the relationship between the moving distance of the recording paper and the elapsed time in such paper feeding control. In this figure, time t. , LI, . . . represent the timing at which a step pulse for moving the recording paper is first applied for each line. Time t. It is assumed that from a stage earlier than that to time t2, the recording paper is moved line by line at intervals of period -T1. During these periods, the tension of the belt for rotating the conveyance roller is kept almost constant, and the recording paper can be accurately moved line by line. However, as shown in the figure, if the period T2 is clearly longer than the period T1 between time t2 and time t3, the conveyance roller will rotate unnecessarily due to the tension of the belt and the inertia of the transmission system. . As a result, as compared with the solid line and the dotted line,
When recording the next line, one line will be recorded at the position after advancing by the overrun distance. If the recording paper is moved at a long cycle T2 and then suddenly moved at a short cycle T1, a phenomenon opposite to this explanation will occur.

When uneven recording paper feeding as explained above occurs, 1
When recording is performed line by line without gaps, so-called white spots occur. Printers used for facsimile machines, etc. may vary in printing cycle.
In such a case, there is a problem that if white spots occur, the quality of the recorded image will deteriorate significantly.

(Object of the Invention) In view of the above circumstances, it is an object of the present invention to provide a paper feed control device that can perform paper feed control that is suitable for following the movement of recording paper.

(Means for achieving the object) In the present invention, the time from the end of printing one line until the signal h1 is received from hX to start the printing operation of the next line is measured, and the length of this time is measured. By changing the step pulse generation timing in accordance with the printing timing, the moving interval of the recording paper is always kept constant at the printing timing, thereby achieving the above-mentioned purpose.

The present invention will be described in detail with reference to Examples below.

(Embodiment) FIG. 2 schematically shows a paper feed control device of this embodiment. - The print controller 1 to the roller 11 of this apparatus are necessary for controlling the printing operations of the printer 1 to the head 12. When the current printing operation is completed and preparation for the next printing is completed, the print controller 11 outputs a print ready signal 13 (FIG. 3a). The print ready signal 13 is supplied to a printing data supplying device (not shown).

When this device prepares the next printing data, it generates a print start signal 14 (FIG. 3b) for starting the printing operation. The print controller 11 receives the print start signal 14, and causes the print ready signal 13 to fall at the rising edge of the print start signal 14. For example, as shown in FIG. 3, the print ready signal 13-1 rises at time t1.
In this case, the print start signal 14-1 is generated after a relatively short period of time has elapsed. Further, in the case of the print ready signal 13-2 rising at time t2, the print start signal 14-2 is generated after a relatively long time has elapsed.

In this way, the time x from when the print ready signal 13 rises to when it falls is not necessarily constant.

The timer circuit 15 is cleared at the rising edge of the print ready signal 13 and starts timing operation. When the time X until the print ready signal 13 falls exceeds a predetermined time α, a long period detection signal 16 (@C in FIG. 3) is output. This time α is set to a value depending on the printing state of the printer. When printing at a recording density of 7.7 lines per millimeter with a facsimile receiver in G[[ mode, this time α is set to, for example, 2 msec. In the example shown in Figure 3,
A long period detection signal 16 is generated for the second generated print ready signal 13-2. The long period detection signal 16 is supplied to a motor pulse generation circuit 17.

FIG. 4 specifically shows the motor pulse generation circuit. The motor pulse generation circuit 17 is supplied with a print start signal 14 and a long period detection image @16. The print start signal 14 is supplied to one input terminal of a first two-man AND circuit 18, and the signal is delayed in a first delay circuit 19. The signal 21 (FIG. 3 d) delayed by the first delay circuit 19 is supplied to one input terminal of the second 12-person AND circuit 22 and further delayed by the second delay circuit 23. . This further delayed signal 24 (Fig. 3d)
) serves as an input signal to the OR circuit 25 and is also supplied to the timer circuit 15, causing the long period detection signal 16 to fall. On the other hand, the long-period detection signal 16 input to the motor pulse generation circuit 17 is supplied to the other input terminal of the second AND circuit 22 and also to the other input terminal of the first AND circuit 18 via the inverter 26. Supplied at the end. The signals output from these AND circuits 18 and 22 also serve as input signals to the OR circuit 25. The OR circuit 25 takes the logical sum of these three input signals and outputs a motor pulse 26 (FIG. 3e). That is, as can be understood from FIG. 3, when the print ready signal 13-1 in which time X is shorter than time α is generated, the motor pulse is generated at the same timing as the print start signal 14 and the delayed signal No. 26 to occur. Further, when the print ready signal 13-2 in which the time X is longer than the time α is generated, the motor pulse 26 is generated at the same timing as the two delayed signals 21 and 24. In this embodiment, when the time α is 2 msec, the delay times of these signals 21 and 24 with respect to the print start signal 14 are set to 1.5 msec and 3.5 msec, respectively.

The motor pulse 26 is supplied to the motor drive circuit 28, and the step pulse 29 (third
Figure f) occurs. Step pulse 29 is supplied to step motor 31 . When the step motor 31 rotates thereby, the conveyor rollers 33, 34 are transferred via the belt 32.
rotates, and the recording paper 35 moves in the sub-scanning direction. The recording paper 35 is configured to move by one line when two step pulses 29 are supplied.

FIG. 3q shows the timing of applying print data 36 to the print head. If it takes some time from the end of recording one line to the start of recording the next line, the first step pulse 29 is generated with a substantial delay. Therefore, the printing positions on each line are approximately equally spaced on the recording paper. FIG. 5 shows these relationships in correspondence with FIG. 1. It can be seen that as a result of adjusting the application timing of the step pulse 29, the overrun distance is substantially absorbed and the printing interval is maintained at a predetermined line interval.

In the embodiment described above, two step pulses are used to move one line, but when one step pulse or three or more step pulses are used to move one line, the pulse generation timing can also be adjusted. By doing so, the line spacing can always be kept constant.

(Effects of the Invention) As described above, in the present invention, the amount of movement of the recording paper is electrically corrected. Therefore, the printer can be manufactured at a lower cost than when mechanical improvements are made such as increasing the tension of the belt or the back tension, and unevenness in recording paper feeding can be sufficiently reduced.

[Brief explanation of the drawing]

Fig. 1 is a characteristic diagram (not shown) of the moving state of recording paper in a conventional paper feed control device, and Figs. 2 to 5 show an embodiment of the present invention. A block diagram of the control device, FIG. 3 is a timing diagram for explaining the operation of this paper feed control device, FIG. 4 is a circuit diagram showing a specific example of the motor pulse generation circuit, and FIG. M5 corresponds to FIG. 1. It is a characteristic diagram. 13...Print ready signal 14...Print start signal 15...
・Timer circuit 16...Motor pulse generation circuit 31...
・Step motor 35...Record paper application: Fuji Xerox Co., Ltd. Representative Patent Attorney Yu Ume Yamauchi

Claims (1)

[Claims] In a printer that uses a step motor to move the recording paper one line at a time and performs recording using a line sequential recording method, a signal is sent to start printing the next line from these times every time one line of printing is completed. and a movement amount adjusting means for changing the application timing of the step pulse to be supplied to the step motor according to the measurement result of each line of the timing means. Characteristic paper feed control device.