JP2994301B2 - Paper edge detection control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper edge detection control device, and more particularly to a paper edge detection control device that can accurately calculate the lower end position of a paper even if an inexpensive paper presence / absence detection sensor is used.

[0002]

2. Description of the Related Art FIG. 8 is a block diagram showing an example of a conventional paper edge detection control device of a printer. Referring to FIG. 8, the paper edge detection control device of the conventional printer includes a paper feed control device 2E and a paper feed mechanism 3. The upper control device 1 is a device that receives and analyzes output data of an upper device such as an electronic computer and outputs a command to the lower paper feed control device 2E, and is located above the paper feed control device 2E. The sheet feed control device 2E detects the lower end of the sheet according to the command sent from the host control device 1 and then sets the number of sheet feed steps 20E in the printable range to the host control device 1E.
Output to

FIG. 7 is a side view of the paper feed mechanism 3. Referring to FIG. 7, the paper feed mechanism 3 uses the stepping motor 31 as a drive source and conveys the paper 5 by rotating the platen 33 via the gear 32. Further, the paper feed mechanism 3 is provided with a sensor 34 for detecting the presence or absence of the paper 5 at a position at a predetermined distance m from the printing surface of the print head 4.

Referring to FIG. 8 in conjunction with FIG. 7, a command input means 21 also serves as a command and a scheduler in the paper feed control device 2E, and controls the transfer of commands between the host control device 1 and the paper feed means 22E. . The command includes information such as the type of sheet feeding operation and the total feed amount.

[0005] The paper feeding means 22E controls the paper feeding mechanism 3 according to this information. The sheet feeding means 22E sets the rotation cycle of the stepping motor 31 for each step in the timer circuit 23. When the set timer value is reached, the timer circuit 23 outputs an interrupt signal 24 to the sheet feeding means 22E and the sensor monitoring means 25. When receiving the interrupt signal 24, the sheet feeding means 22 E rotates the stepping motor 31 by one step, and sets the next rotation cycle in the timer circuit 23.

When the sensor monitoring means 25 receives the interrupt signal 24, it checks the state of the sensor 34. Sensor 3
Reference numeral 4 denotes the presence or absence of the paper 5 as an electric signal level. As a result of checking the presence or absence of the paper 5 by the sensor monitoring unit 25,
If the paper level is present, the paper flag 26 is set to "1",
If the level is that there is no paper, the paper flag 26 is set to “0” and output to the counting means 27. The counting means 27 does not count the counter 28 while the paper flag 26 is "1". When the paper flag 26 becomes "0", the counting means 27 increments the counter 28 by one. Therefore, the counter 28 records the number 20 of sheet feeding steps of the stepping motor 31 from the time when the sensor 34 detects the lower end position of the sheet 5. By receiving the sheet feed step number 20 from the counter 28, the host controller 1 determines the lower end position of the sheet 5.

[0007]

This conventional paper end detection control device employs a physical system as a sensor which detects the presence or absence of a sheet by the action of a rotational moment generated by directly contacting a sheet with a lever. In this case, since an inertial force due to the rotational moment acts on the lever, a problem may occur that the operation of the lever does not follow the paper feed speed, especially when the paper feed speed is high.

When the host controller performs control to stop printing when the number of paper feed steps after the detection of the lower end of the paper reaches the printing limit, the speed at which the lower end of the paper passes over the sensor is determined by the sensor. If the response time is sufficiently negligible, printing can be stopped at a position close to the printing limit position (FIG. 9A), but if the response time of the sensor cannot be ignored, the speed at which the lower end of the paper passes over the sensor can be stopped. As the printing speed increases, printing stops at a lower position (FIG. 9B).

Conventionally, as means for avoiding this problem,
In many cases, a sensor with a fast response time is used, but a sensor with a fast response speed has a problem that the cost is high at present.

An object of the present invention is to provide a paper edge detection control device which can accurately calculate the lower edge position of a paper even if an inexpensive paper presence / absence detection sensor is used.

[0011]

[0012]

According to the present invention, there is provided a sheet edge detection control device comprising: a sensor for detecting the presence or absence of a sheet by a mechanical rotary lever; and a stepping motor for conveying the sheet after the sensor detects the lower end of the sheet. A counter for counting the number of drive steps of the speed, speed detecting means for detecting the paper feed speed,
Speed change identification means for identifying an acceleration, constant speed, and deceleration state during the sheet conveyance; and acceleration, constant speed, and speed during the sheet conveyance identified by the sheet feed speed and the speed change identification means detected by the speed detection means. A second correction table for outputting a correction value corresponding to the deceleration state, and the number of sheet feeding steps for calculating the true lower end position of the sheet by adding the contents of the counter and the correction value are transmitted to the host controller. Counter correction means.

[0013]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 1 showing a block diagram of a first embodiment of the present invention, a paper edge detection control device of this embodiment comprises a paper feed control device 2 and a paper feed mechanism 3. The upper control device 1 is a device that receives and analyzes output data of an upper device such as an electronic computer and outputs a command to the lower paper feed control device 2, and is positioned above the paper feed control device 2. The sheet feed control device 2 detects the lower end of the sheet according to the command sent from the host control device 1 and then outputs the number of sheet feed steps 20 in the printable range to the host control device 1.

FIG. 7 is a side view of the paper feed mechanism 3. Referring to FIG. 7, the paper feed mechanism 3 uses the stepping motor 31 as a drive source and conveys the paper 5 by rotating the platen 33 via the gear 32. Further, the paper feed mechanism 3 is provided with a sensor 34 for detecting the presence or absence of the paper 5 with a mechanical rotating lever at a position at a predetermined distance m from the printing surface of the print head 4.

Referring to FIG. 1 in conjunction with FIG. 7, the command input means 21 also functions as a command and a scheduler in the paper feed control device 2, and controls the transfer of commands between the host control device 1 and the paper feed means 22. . The command includes information such as the type of sheet feeding operation and the total feed amount.

The paper feed means 22 controls the paper feed mechanism 3 according to this information. The paper feeding means 22 determines the rotation cycle of the stepping motor 31 for each step by the timer circuit 2.
Set to 3. When the timer circuit 23 reaches the set timer value, the sheet feeding means 22 and the sensor monitoring means 25
, An interrupt signal 24 is output. When the paper feed means 22 receives the interrupt signal 24, the stepping motor 31
Is turned one step, and the next rotation cycle is set in the timer circuit 23.

When the sensor monitoring means 25 receives the interrupt signal 24, it checks the state of the sensor 34. Sensor 3
Reference numeral 4 denotes the presence or absence of the paper 5 as an electric signal level. As a result of checking the presence or absence of the paper 5 by the sensor monitoring unit 25,
If the paper level is present, the paper flag 26 is set to "1",
If the level is that there is no paper, the paper flag 26 is set to “0” and output to the counting means 27. The counting means 27 does not count the counter 28 while the paper flag 26 is "1". When the paper flag 26 becomes "0", the counting means 27 increments the counter 28 by one and outputs it to the counter correcting means 29. The counter correction means 29 adds the speed correction value in the correction table 202 to the output data of the counter 28 and outputs the result to the host controller 1 as the number of paper feed steps 20.

When the paper flag 26 is switched from "1" to "0", the correction table 202 indicates that the speed detecting means 20
A speed correction value corresponding to the sheet feed speed detected in step 1 is derived and output. The paper feed speed is a plurality of types of paper feed speeds when the printing speed is changed depending on the type of the paper 5, for example, copy paper, postcards, etc. In one paper feed operation, the number of steps per second during the constant speed operation is determined. No, it is detected by the speed detecting means 201.

FIG. 2 is a diagram showing an example of the contents of the correction table 202 by specific numerical values. The response time T of the sensor 34 is fixed at T = 50 [milliseconds], and the paper feed speed of the paper feed mechanism 3 is S1 = 1000, S2 = 200.
0, S3 = 3000 (all units are [steps / second]), the speed correction value is S
Δ1, δ2, δ3 corresponding to 1, S2, S3.
In this example, δ1, δ2, δ3 are obtained as (response time T) × (speed data) [step], and δ1 = 50, δ2 = 100, δ3 = 150 (all units are [step]) as speed correction values. ) Is stored.

FIG. 3 is a waveform diagram for explaining an example of the operation of this embodiment.
6 is a time chart showing the speed of the stepping motor 31 and the state of the paper flag 26 when executing a command to feed the paper at = 3000 [steps / second]. Here, the distance m from the print surface by the print head 4 to the sensor 34 is m =
400 [steps]. The operation of this embodiment will be described with reference to FIG. 1, FIG. 2 and FIG.

The paper feeding means 22 has a paper feeding speed S3 =
3000 [steps / second], the stepping motor 31
Drive. When the sensor monitoring unit 25 detects the no paper level of the sensor 34, it changes the paper flag 26 from "1" to "0".
To When the paper flag 26 changes from "1" to "0", the counting means 27 starts counting by the counter 28. The counter correction means 29 determines that the sheet feed speed S3 detected by the speed detection means 201 is 3000 [step /
Seconds] and the speed correction value δ3 = 1 according to the correction table 202.
Guide 50 [steps]. The speed correction value δ3 = 150 [steps] is the number of sheet feeding steps sent from the time Ta when the lower end of the sheet passes the sensor 34 to the time Tb when the sensor 34 actually reaches the no-paper level. The counter correction means 29 adds the speed correction value δ3 to the contents of the counter 28.
= Paper feed step number 2 with 150 [steps] added
By transmitting 0 to the host controller 1, the host controller 1 can calculate the true sheet lower end position.

In the first embodiment, when the paper feed speed detects the lower end of the paper in the constant speed region, printing can be stopped at the print limit position by the correction using the uniform speed correction value, but the paper feed speed increases. If this uniform speed correction data is applied when the lower end of the sheet is detected in the area or the deceleration area, a problem occurs in that printing stops above the print limit position.

FIG. 4 is a block diagram showing a second embodiment of the present invention. Referring to FIG. 4, the paper edge detection control device of this embodiment is different from the first embodiment in that the speed change identification means 2 in the paper feed control device 2A is different from that of the first embodiment.
The difference is that 04 is added and the contents of the correction table 203 are changed.

The speed change discriminating means 204 includes a timer circuit 23
By comparing the rotation period before reaching the timer value set in step S3 with the rotation period after inputting the interrupt signal 24, it is determined whether the paper feed speed is in the acceleration, constant speed, or deceleration state. . As a discrimination method, as shown in FIG. 6, if the rotation period before reaching the timer value is A1 and the rotation period after inputting the interrupt signal 24 is A2, acceleration is performed when A1> A2, and acceleration is performed when A1 = A2. At the time of constant speed, and when A1 <A2, it is at the time of deceleration.

FIG. 5 is a diagram showing an example of the contents of the correction table 203 by specific numerical values. Since the sensor 34 detects the end of the sheet by a mechanical rotation lever, the response time changes depending on the acceleration, constant speed, and deceleration of the sheet.
Therefore, the response time of the sensor 34 is set to T1 for acceleration.
= 30 [millisecond], at the time of constant speed: T2 = 50 [millisecond], at the time of deceleration: T3 = 70 [millisecond], and the paper feed speed of the paper feed mechanism 3 is S1 = 1000, S
2 = 2000, S3 = 3000 (all units are [step / second]), the correction values correspond to the paper feed speeds S1, S2, and S3, and the acceleration correction values α1,
α2, α3, correction values β1, β2, β3 at constant speed, and correction values γ1, γ2, γ3 at deceleration.

[0027]

As described above, according to the present invention,
When the paper detection lever operates and the sensor responds, the data is converted to the number of steps in the state of the paper feed speed, that is, in the case of acceleration, constant speed, and deceleration. The output limit is added to the paper feed counter and output to the host controller. Therefore, even if the paper feed speed is detected not only in the constant speed area but also in the acceleration area and the deceleration area, the print limit position can be accurately grasped. There is an effect that it becomes.

Further, as a sheet detecting method, there is an effect that an inexpensive lever for physically detecting the presence or absence of a sheet can be used by the action of a rotational moment generated by directly contacting the sheet.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a diagram illustrating a correction table according to the first embodiment.

FIG. 3 is a waveform chart illustrating an example of the operation of the first embodiment.

FIG. 4 is a block diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 5 is a diagram illustrating a correction table according to the second embodiment.

FIG. 6 is a diagram illustrating an acceleration, a constant speed, and a deceleration state of a sheet feeding speed according to a second embodiment.

FIG. 7 is a diagram illustrating a configuration of a sheet feeding mechanism.

FIG. 8 is a block diagram showing a configuration of a conventional example.

FIG. 9 is a diagram illustrating a printing state at the lower end of a sheet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper control device 2, 2A Paper feed control device 20, 20A Number of paper feed steps 21 Command input means 22, 22A Paper feed means 23 Timer circuit 24 Interrupt signal 25 Sensor monitoring means 26 Paper flag 27 Counting means 28 Counter 29 Counter correcting means 201 Speed detection Means 202, 203 Correction table 204 Speed change identification means 3 Paper feed mechanism 31 Stepping motor 32 Gear 33 Platen 34 Sensor 4 Print head 5 Paper

Claims (1)

(57) [Claims] 1. A sensor for detecting the presence or absence of a sheet with a mechanical rotary lever, a counter for counting the number of drive steps of a sheet transport stepping motor after the sensor detects the lower end of the sheet, and a sheet feed speed. Speed detecting means; speed change identifying means for identifying an acceleration, constant speed, and deceleration state during the sheet conveyance; and a sheet feed speed detected by the speed detecting means and a speed change during the sheet conveyance identified by the speed change identifying means. A second correction table for outputting correction values corresponding to the acceleration, constant speed, and deceleration states; and the number of sheet feeding steps for calculating the true lower end position of the sheet by adding the contents of the counter and the correction value. A sheet edge detection control device, comprising: a counter correction means for transmitting to a control device.