JP2002187311A - Recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recorder capable of preventing deterioration of image quality due to variation in feeding of a paper. SOLUTION: This recorder has a paper supply device for supplying a paper 3 and a recording means 2 for recording on the paper 3. The recorder is equipped with a means for measuring an amount of fed paper. A position of print data to be sent to a printing head 2 is varied corresponding to the measured result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus provided with a picture paper apparatus for supplying a recording medium to a recording section.

[0002]

2. Description of the Related Art Conventionally, in a recording apparatus, a method has been used in which a paper feed amount is detected by an encoder attached to a paper feed roller, and the paper feed amount is controlled by controlling a paper feed motor. JP-A-5-004392). Also, there is a method of performing control so that an error of one step or less of a stepping motor is not accumulated (Japanese Patent Laid-Open No. 7-1995).
No. 314838).

[0003]

However, in the conventional paper feed only by the control of the motor, there is a limit in increasing the stop precision due to friction and inertia. When the paper is fed too much, complicated control such as reversing the motor has been performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a recording apparatus capable of preventing deterioration of image quality due to uneven paper feeding.

[0005]

According to a first aspect of the present invention, there is provided a paper feeder for feeding a sheet and a recording apparatus having a recording means for recording on the sheet. Means for changing the position of the print data to be sent to the print head in accordance with the measurement result.

According to a second aspect of the present invention, in a recording apparatus having a paper feeding device for supplying paper and a recording means for recording on the paper, the paper is fed by a stepping motor to measure the thickness of the paper. Provides a means to specify the paper thickness or paper type, and corrects the paper feed amount based on the paper thickness by changing the paper feed amount of the stepping motor and the position of the print data sent to the print head. Features.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1> FIG. 1 is a diagram showing print data, a print head, and a sheet in a printing apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes a memory in which print data is stored; Is a sheet to be printed.

[0009] Of the data stored in the memory 1, data to be printed by this pass is transferred to the head 2 in accordance with the movement of the head 2 and printed on the paper 3. Here, it is assumed that the printable elements on the head 2 are arranged in 256 at 1200 dpi intervals, and the paper feed is controlled by a motor to be ± 10%.
It is assumed that a feeding accuracy of 0 μm is obtained.

Since 1200 dpi is about 21 μm,
To correct 100 μm, it is sufficient that 5 dots or more are provided. If 8 dots are prepared with a margin, 1 to 8 and 249 to 256
Is used for correction, and printing is normally performed with 240 elements of 9 to 248. If the error of the paper feed is 0, the data from the memory 1 is sent to 9 to 248 of the head 2, and 1 to 8 and 249 are sent.
0 is sent to 256 to perform printing. For example, when it is detected that the paper 3 has been sent too much by 80 μm, since 80 μm corresponds to about 4 elements of the head 2, it is shifted by 4 elements of data from the memory 1 and sent to 5 to 244 of the head 2, and By sending 0 to ４4 and 245 to 256, the printing range is shifted in the paper feed direction to correct the overfeed of the paper 3.

If the feeding of the paper 3 is insufficient, the data transfer to the head 2 is shifted in the reverse direction and corrected.

As a method of detecting the paper feed amount, an encoder pattern is attached to the circumference of the platen roller, an encoder is attached to the paper feed motor, or as shown in FIG. A method of attaching the encoder 5 is conceivable.

<Second Embodiment> Next, a second embodiment of the present invention will be described.

When paper is fed by a stepping motor, for example, the paper feed amount per pulse is 1/300 inch.
In this case, even if the feed amount is corrected based on the paper thickness, the paper feed amount cannot be controlled below this.

Here, the procedure for correcting the paper feed amount by the paper feed by the motor and the data feed to the head will be described with reference to the flowchart shown in FIG.

When a paper feed command is received from the host device, the paper feed amount WL is instructed thereby. The paper thickness is estimated from the paper type set on the print screen or the paper thickness is obtained from a value obtained from a paper thickness detector, and the paper feed correction amount W1 for WL is obtained. And the previous paper surplus amount WLn
By adding (−1), the current paper feed amount WLn is calculated.

In the next step, the paper feed amount by the pulse of the stepping motor among the current paper feed amounts is obtained. The current paper feed amount WLn is divided by the paper feed amount per pulse WLpm, and the result is rounded to obtain the number of pulses Pn.

As described above, WLpm ×
The paper is fed by Pn, and the surplus paper amount this time is WLn (1)
Becomes This extra amount is added to the correction at the next paper feed.
Then, this surplus amount is corrected by data transferred to the head.

The remaining amount WLn (1) of the paper feed is divided by the dot pitch HL of the head, rounded off, and the number of corrected dots Hn by the dots of the head is obtained. For example, if the paper feed amount per pulse of the pulse motor is 1/300 inch and the dot pitch of the head is 1200 dpi, the paper feed amount of one pulse of the motor is equivalent to 4 dots. Therefore,
When the number of printable elements of the head is 256 from 1 to 256,
Two dots on both sides are left for correction, and data of 0 is sent. Normally, print data is sent to 252 dots of 3 to 254 in the middle to perform printing.

If the paper is fed over 20 μm by the motor, the data is shifted to the head by one dot and transferred.
Over-feeding is corrected by printing using 253 dots.

[0021]

As is apparent from the above description, according to the present invention, even if an inexpensive paper feed control device is used, a paper feed error can be corrected to within 1/2 dot, and The effect is obtained that deterioration of image quality due to unevenness can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating print data, a recording head, and a sheet in a recording apparatus according to a first embodiment of the present invention.

FIG. 2 is a perspective view illustrating a method of measuring a paper feed amount.

FIG. 3 is a flowchart showing a procedure for correcting a paper feed amount by a paper feed by a motor and a method of feeding data to a head in the recording apparatus according to the second embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Memory 2 Head (recording means) 3 Paper 4 Platen roller 5 Encoder

Claims (2)

[Claims] 1. A recording apparatus having a paper feeding device for supplying paper and a recording means for recording on paper, comprising means for measuring a paper feed amount, and a position of print data to be sent to a print head in accordance with the measurement result. A recording device characterized by changing the following. 2. A recording apparatus having a paper feeding device for feeding paper and a recording means for recording on the paper, wherein the paper is fed by a stepping motor to measure the thickness of the paper or the thickness of the paper or A recording apparatus provided with means for designating a paper type, and correcting a paper feed amount based on a paper thickness by changing a paper feed amount of a stepping motor and a position of print data to be sent to a print head.