JP3046722B2 - Printer paper feeder - 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 feeder for a printer, and more particularly to a paper feeder for a printer capable of performing paper feed control with high accuracy.

[0002]

2. Description of the Related Art In general, a paper feeder of a printer transmits the rotation of a paper feed motor to a paper feed roller via a group of drive gears, and rotates the paper feed roller to convey a predetermined sheet by a predetermined amount. Is formed.

When a line feed operation is performed, the paper feed amount required for the line feed is calculated, and the rotation amount of the paper feed motor is obtained based on the outer peripheral length of the paper feed roller and the mechanism of the drive gear group. The paper feed motor is rotated by the rotation amount.

[0004] By driving the print head based on a desired print signal while moving the carriage, desired print is performed on paper.

However, in the above-mentioned conventional printer, the paper feed roller is eccentric due to the eccentricity of the gears constituting the drive gear group between the paper feed roller and the paper feed motor, the paper feed roller is produced due to factors such as manufacturing errors and temperature changes. In this case, the amount varies, and particularly when performing graphic printing, the variation in paper feeding accuracy causes a decrease in print quality.

Japanese Patent Laid-Open No. 193563/1992 discloses a method for suppressing such a variation in paper feeding accuracy. In the publication, a reference roller is formed of a hard material having a small dimensional change with respect to temperature, and the reference roller is disposed so as to be in contact with a part of the sheet conveyed by a sheet feed roller, and the sheet feed speed and While making the rotation peripheral speed of the reference roller equal, a slit disk is provided coaxially with this reference roller, the rotation angle of the reference roller is detected by a photo sensor, and the detection result is fed back to the controller to feed the paper feed motor. The paper feed amount can be accurately determined by controlling the operation.

[0007]

However, in the conventional paper feeder, the paper feed is performed while sequentially detecting the rotation angle of the reference roller by a photo sensor using a slit disk attached to the reference roller. Since the operation of the motor is controlled, a reference roller and a slit disk are required when controlling the driving of the paper feed motor, which leads to an increase in the number of parts and an increase in manufacturing cost. have.

Further, with respect to variations in the outer peripheral length due to the manufacturing accuracy and temperature change of the reference roller, the positional relationship between a large number of slits formed in the slit disk is accurately manufactured to improve dimensional accuracy. In addition, when there is a manufacturing error, it is necessary to correct the paper feed amount by increasing or decreasing the number of slits of the slit disk using a photo sensor or the like, and it becomes extremely difficult to control the driving of the paper feed motor. In addition, in order to increase the paper feeding accuracy, the slit disk must be finished to have excellent dimensional accuracy, and there is a problem that the manufacturing cost is further increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is possible to significantly improve the paper feeding accuracy without always using a reference roller, and to reduce the manufacturing cost. It is an object to provide a feeding device.

[0010]

According to a first aspect of the present invention, there is provided a paper feeder for a printer, comprising:
A paper feed roller that is driven to rotate by a paper feed motor to convey a predetermined sheet, and an outer circumference of the paper feed roller is brought into contact with a part of the paper conveyed by the paper feed roller so that the outer circumference length is equivalent to one line feed. A rotatable paper feed reference roller formed to have the same length as the length of the paper feed reference line, a line feed position detector for detecting the amount of rotation of the paper feed reference roller, and a detection signal from the line feed position detector. A counter for counting the number of drive steps of the stepping motor when the paper feed reference roller makes one rotation from the drive step position at the initial position of the paper feed roller, and cumulatively counting the number of drive steps required for one line feed operation; The number of driving steps of the stepping motor necessary for one rotation of the paper feed roller is divided in advance into a plurality of parts by a predetermined division number P (P is an integer). A determination circuit which determines which position of the drive step in the initial position of the line is closest to which of the division steps, and determines the closest division step as a start position of a line feed operation, and a start position by this determination circuit A storage device for storing the divided step position and the number of drive steps counted by the counter from the divided step as a corrected drive step number, and driving the paper feed motor based on the corrected drive step number stored in the storage device And a control device for performing control.

Further, according to a second aspect of the present invention, the storage device stores a division step position at which each line feed operation is started while the paper feed roller makes one rotation and a number of correction drive steps. The invention according to claim 3 is characterized in that a detected portion for detecting an initial position at the time of printing is formed on the paper feed roller, and an initial position detection for detecting the detected portion is performed. It is characterized by having arranged a vessel. Further, the invention of claim 4 is characterized in that the paper feed reference roller and the line feed position detector are configured to be detachable.

[0012]

According to the paper feeding device of the printer according to the present invention,
First, in a state where the paper feed reference roller and the line feed position detector are mounted, the paper feed motor is driven to position the paper feed roller at the initial position, and the drive start position of the paper feed motor in this state is stored in the storage device in advance. Then, the paper feed motor is driven to rotate the paper feed roller, so that the paper feed reference roller is also rotated, and the rotation amount of the paper feed reference roller is detected by a line feed position detector. While detecting, the counter counts the number of drive pulses of the paper feed motor until the paper feed reference roller makes one rotation, that is, the number of drive pulses required for one actual line feed operation. Next, the determination circuit determines which of the preset dividing steps the drive start position of the paper feed motor is closest to, and stores the closest division step as the drive start position in the storage device. At the same time, the number of correction drive pulses required for one line feed operation accumulated by the counter is stored. This operation is repeated for N line feeds until the paper feed roller makes one rotation, and the division step position and the number of correction drive steps for starting the line feed operation of each line feed operation for one rotation of the paper feed roller are stored. When the adjustment operation of the line feed step is completed by this operation, the paper feed reference roller and the line feed position detector are removed.

Then, the paper feed motor is driven and controlled by the number of correction drive steps from the division step at which the line feed start position is stored in the storage device, and the paper feed roller is rotated to convey the paper by a predetermined amount. Line feed is performed, so that even if the paper feed reference roller is removed, the drive control of the paper feed motor is performed while sequentially detecting one line feed amount by the paper feed reference roller. The paper feed control can be performed with the precision described above.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows an embodiment of a paper feeder of a printer according to the present invention, in which a predetermined paper 1 is used for printing by a print head such as a thermal head (not shown).
The paper feed roller 2 is provided rotatably. The outer circumference of the paper feed roller 2 is set to a length corresponding to N line feed pitches. In the vicinity of the paper feed roller 2, a stepping motor 3 as a paper feed motor that is rotated and driven in minute steps is provided. A drive gear 5 is attached to an output shaft 4 of the stepping motor 3. I have. Also, the rotation shaft 6 of the paper feed roller 2
Has a rotating gear 7 attached thereto.
A transmission gear 8 for transmitting the rotation of the drive gear 5 to the rotary gear 7 is meshed between the drive gear 5 and the drive gear 5. Further, on the end face of the paper feed roller 2, a detection portion 9 such as a slit or a reflection plate serving as a reference for detecting an initial position at the time of printing is formed. Is provided with an initial position detector 10 such as a photo sensor for detecting the detected portion 9.

A paper feed reference roller 11 arranged in parallel with the rotation shaft 6 of the paper feed roller 2 is in contact with the outer periphery of the paper feed roller 2 via the paper 1. The feed reference roller 11 is configured to rotate with the conveyance of the sheet 1 by the rotation of the paper feed roller 2. Further, the outer peripheral length of the paper feed reference roller 11 is:
The length is set to the length of one line feed when the sheet 1 performs a line feed operation, and the paper feed reference roller 11 makes one rotation for each line feed operation of the sheet 1.

A decoding plate 13, which is a member to be detected, is attached to the rotating shaft 12 of the paper feed reference roller 11 so as to rotate integrally with the paper feed reference roller 11. A plurality of slits 14 as the detected part 9 are formed on the outer periphery. Further, on the outer peripheral portion of the decoding plate 13, the slits 14 are provided.
A line feed position detector 15 such as a photo sensor for detecting the line feed is provided. In the present embodiment, the paper feed reference roller 11, the decoding plate 13, and the line feed position detector 1 are used.
5 is, for example, a detachable unit, and is attached only at the time of manufacture or maintenance of the device.
It is designed to be removed when using the device.

Further, in the present embodiment, a control device 16 which receives detection signals from the initial position detector 10 and the line feed position detector 15 and controls the driving of the stepping motor 3 is provided. The control device 16 includes:
A counter 17 for counting the cumulative number of driving steps of the stepping motor 3 is provided, and a determination circuit 18 for determining a predetermined line feed start position is provided. Further, a storage device 19 such as a memory is connected to the control device 16.

The control unit 16 previously divides the number of drive steps of the stepping motor 3 required for one rotation of the paper feed roller 2 into a plurality of divisions by a predetermined division number P (P is an integer). The drive control of the stepping motor 3 is performed based on the number of steps. For example, as shown in FIG.
If the number of drive steps of the stepping motor 3 required for rotation is 8960, and the number of divisions P is 64, the number of drive steps of the stepping motor 3 for rotating the paper feed roller 2 once is divided every 140 steps. Will be.

The counter 17 counts the number of drive steps of the stepping motor 3 when the paper feed reference roller 11 makes one rotation from the drive step position at the initial position of the paper feed roller 2, and is necessary for one line feed operation. The number of driving steps is cumulatively measured. On the other hand, the determination circuit 18 determines which of the division steps the drive step position at the initial position of the paper feed roller 2 is closest to, and sets the closest division step as the start position of the line feed operation. Then, the number of driving steps counted by the counter 17 from the division step set as the start position is stored in the storage device 19 as the number of corrected driving steps.

This operation is repeated until the paper feed roller 2 makes one rotation, and the division step position and the number of correction drive steps for starting the line feed operation for each line feed operation for one rotation of the paper feed roller 2 are stored. Stored in the device 19,
After the storage, the control device 16 controls the stepping motor 3 based on the data stored in the storage device 19.
Drive control.

Next, the operation of this embodiment will be described.

In this embodiment, when adjusting the line feed operation step, first, the unitized paper feed reference roller 11, decoding plate 13 and line feed position detector 15
Is mounted, and in this state, the stepping motor 3 is driven to rotate the paper feed roller 2 until the detected position 9 is detected by the initial position detector 10, and the paper feed roller 2 is moved to the initial position. Position. The driving start position of the stepping motor 3 in this state is stored in the storage device 19 in advance, and then the stepping motor 3 is driven to rotate the paper feed roller 2 so that the paper feed reference roller 11 is also rotated. When the slit 14 of the decoding plate 13 is detected by the line feed position detector 15, the counter 17 of the control device 16 causes the paper feed reference roller 11 to rotate.
The number of drive pulses of the stepping motor 3 until the first rotation of the motor, ie, the number of drive pulses required for one actual line feed operation is cumulatively measured.

Next, the determination circuit 18 of the control device 16 determines which of the previously set division steps the drive start position of the stepping motor 3 is closest to, and the storage device 19 determines this position. The closest division step is stored as a drive start position, and the number of correction drive pulses necessary for one line feed operation accumulated by the counter 17 is stored. Such an operation is repeated for N line feeds until the paper feed roller 2 makes one rotation, and the division step position and the number of correction drive steps for starting the line feed operation of each line feed operation for one rotation of the paper feed roller 2 Is stored in the storage device 19.

When the adjustment operation of the line feed step is completed by the above operation, the unitized paper feed reference roller 1
1. The decoding plate 13 and the line feed position detector 15 are removed.

Next, when paper is fed by using the paper feeder, a predetermined paper 1 is inserted into the outer peripheral portion of the paper feed roller 2 and based on the stored data stored in the storage device 19. By driving the stepping motor 3 by the control device 16, the paper feed roller 2 is rotated via the drive gear 5, the transmission gear 8, and the rotary gear 7 to convey the paper 1 by a predetermined amount and to perform a line feed. It is supposed to do it. That is, the line feed operation is performed by driving the stepping motor 3 by the number of correction drive steps from the division step at which the line feed start position stored in the storage device 19 is stored.
Even if is removed, the paper feed control can be performed with almost the same accuracy as when the drive control of the stepping motor 3 is performed while sequentially detecting one line feed amount by the paper feed reference roller 11.

Therefore, in the present embodiment, the line feed operation of each rotation of the paper feed roller 2 is started in advance in the storage device 19 using the paper feed reference roller 11 at the time of manufacture or maintenance. The division step position and the number of each correction drive step are stored, and thereafter,
The paper feed reference roller 11 is removed and the storage device 1 is removed.
The drive control of the stepping motor 3 is performed based on the stored data of No. 9 and the drive control of the stepping motor 3 is performed using the correction data based on the division step without using the paper feed reference roller 11 during normal driving. With this configuration, paper feeding can be performed with high accuracy equivalent to that in the case of performing drive control while sequentially correcting using the paper feeding reference roller 11 without using the paper feeding reference roller 11. Further, the paper feed reference roller 11, the decoding plate 13, and the line feed position detector 15 are unitized to be detachable, so that the paper feed reference roller 11 and the like can be used only when the correction data is stored in the storage device 19. The paper feed reference roller 11 and the like are not required,
The number of parts can be significantly reduced, and the manufacturing cost can be significantly reduced.

The present invention is not limited to the above-described embodiment, and various modifications can be made as necessary, for example, when the present invention is applied to color printing.

[0029]

As described above, the paper feeder of the printer according to the present invention uses a paper feed reference roller in advance in the storage device for each line feed operation for one rotation of the paper feed roller during manufacturing or maintenance. The position of a division step at which a line feed operation is started and the number of correction drive steps are stored. Thereafter, the paper feed reference roller is removed, and drive control of the paper feed motor is performed based on data stored in the storage device. Since the drive control of the paper feed motor is performed using the correction data based on the division step without using the paper feed reference roller during normal driving,
Paper feed can be performed with the same high accuracy as in the case of performing drive control while sequentially correcting using the paper feed reference roller without using the paper feed reference roller. Further, the paper feed reference roller, the decoding plate and the line feed position detector are unitized and made detachable, so that the paper feed reference roller or the like may be used only when the correction data is stored in the storage device. There is no need for a reference roller or the like, so that the number of parts can be greatly reduced, and the production cost can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part showing an embodiment of a paper feeding device of a printer according to the present invention.

FIG. 2 is an explanatory diagram showing a relationship between a driving step and a dividing step by the control device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Paper 2 Paper feed roller 3 Stepping motor 5 Drive gear 7 Rotating gear 8 Transmission gear 9 Detected part 10 Initial position detector 11 Paper feed reference roller 13 Decode plate 14 Slit 15 Line feed position detector 16 Control device 17 Counter 18 Judgment circuit 19 Storage device

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B41J 19/92 B41J 13/00 B41J 13/02

Claims (4)

(57) [Claims] A paper feed roller rotatably driven by a paper feed motor for transporting a predetermined paper; and an outer periphery in contact with an outer periphery of the paper feed roller via a part of the paper transported by the paper feed roller. A rotatable paper feed reference roller having a length equal to the length of one line feed, a line feed position detector for detecting the amount of rotation of the paper feed reference roller, and A detection signal is input, the number of drive steps of the stepping motor when the paper feed reference roller makes one rotation from the drive step position at the initial position of the paper feed roller is counted, and the number of drive steps required for one line feed operation is accumulated. The counter to be measured and the number of driving steps of the stepping motor required for one rotation of the paper feed roller are divided into a plurality of parts by a predetermined division number P (P is an integer). A determination circuit for determining which of the division steps the drive step position at the initial position of the paper feed roller is closest to, and a determination circuit for setting the closest division step as a start position of a line feed operation; A storage device for storing the divided step position and the number of drive steps counted by the counter from the divided step as a corrected drive step number, and the paper feed based on the corrected drive step number stored in the storage device. A paper feeder for a printer, comprising: a control device for controlling driving of a motor. 2. The storage device according to claim 1, wherein the paper feed roller is
2. The paper feeder for a printer according to claim 1, wherein a division step position at which each line feed operation is started during rotation and a number of correction drive steps are stored. 3. A paper feed roller, wherein a detected portion for detecting an initial position at the time of printing is formed, and an initial position detector for detecting the detected portion is provided. A paper feeder for a printer according to claim 1. 4. A paper feed device for a printer according to claim 1, wherein said paper feed reference roller and said line feed position detector are detachably configured.