JPH04236565A - Paper carrier control system for original reader - 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]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper conveyance control system for temperature correction of paper feed amount in a paper conveyance type document reading device such as a character reading device OCR or an image scanner. When a paper feed roller made of an inexpensive material such as urethane is used in a document reading device, the accuracy of the paper feed amount tends to decrease. The present invention aims to improve the accuracy of the paper feed amount when such a feed roller is used.

0002

2. Description of the Related Art FIG. 4 shows the internal structure of a conventional paper conveyance type document reading device. In the figure, 1 is a motor, 2 is a feed roller, 3 is a belt, 4 is a driven roller, 5 is a reading unit, 6
7 is a fluorescent lamp, 7 is a CCD, and 8 is paper (original). When the motor 1 rotates, the belt 3 causes the feed roller 2 to rotate in the direction of the arrow, and the paper 8 is fed from the right under the reading unit 5 by the feed roller 2 and the driven roller 4, and is ejected to the left. When the paper 8 passes under the reading unit 5, it is illuminated by the fluorescent lamp 6 and read by the CCD 7.

[0003] The feed roller 2 has conventionally been made of a metal material in order to feed the paper with high precision, but the material cost and the number of processing steps are large, making the document reading device expensive. Therefore, feed rollers made of inexpensive materials such as urethane are also used. However, in the case of urethane feed rollers, for example, the roller diameter is likely to change due to temperature increases caused by heat generated by fluorescent lights, and due to manufacturing, variations in roller diameter, surface roughness, hardness, inter-roller pressure, etc. are likely to occur, and paper feed Accuracy was significantly affected.

0004

[Problems to be Solved by the Invention] In conventional document reading devices that use feed rollers made of inexpensive materials such as urethane, the amount of paper feed is easily affected by temperature. Inconveniences such as expansion and contraction and shifting of the image cutting position on the paper occurred. Furthermore, since there are large manufacturing variations in the feed roller, there is also the disadvantage that inspection and adjustment require a large number of man-hours. SUMMARY OF THE INVENTION An object of the present invention is to provide a means for improving the accuracy of paper feed amount due to temperature changes and manufacturing variations in a document reading device using a feed roller made of an inexpensive material such as urethane.

[0005]

[Means for Solving the Problems] The present invention detects the ambient temperature of the feed roller and changes the feed control amount for the motor that drives the feed roller so that the feed amount is not affected by the temperature. The influence of variations in the feed roller is eliminated by detecting the difference between the feed control amount and the actual feed amount for the feed roller at the manufacturing stage and initially correcting the feed control amount. FIG. 1 is a diagram showing the basic configuration of the present invention. In FIG. 1, 1 is a motor for driving paper feed. For example, a pulse motor. 2 is a feed roller. 3 is a belt that drives the feed roller. 4 is a driven roller that faces the feed roller. 5 is a reading unit. 6 is a fluorescent lamp that illuminates the reading surface of the paper. 7 is a CCD that reads the image on the paper surface. 8 is paper.

Reference numeral 9 denotes a temperature sensor attached near the feed roller. 10 is a control device. Reference numeral 11 denotes a paper feed amount initial correction processing unit that performs processing to correct errors in the paper feed amount due to variations in the feed roller. Reference numeral 12 denotes a paper feed amount temperature correction processing unit that performs processing to correct changes in the paper feed amount due to changes in the temperature of the feed roller. T0 is the reference temperature for correction. α is an initial correction coefficient. Hi is the paper feed control amount before initial correction, and is, for example, the pulse drive frequency of the pulse motor. H0 is an initial paper feed control amount that is initially corrected by multiplying Hi by (1+α). β is a temperature correction coefficient for correcting changes in the paper feed amount due to changes in the temperature of the feed roller, and is determined in advance based on the temperature change characteristics of the diameter of the feed roller. T1 is the temperature during operation. H1 is a corrected paper feed control amount that is temperature-corrected by multiplying H0 by (1+β(T1 - T0)).

[0007]

[Function] In FIG. 1, the paper feed amount initial correction processing section 11 is activated at the time of shipping adjustment of the document reading device, etc.
Using the temperature near the feed roller 2 measured by the temperature sensor 9 as a reference temperature T0, the error in the actual paper feed amount with respect to the control amount for feeding the paper 8 is determined, and the initial correction coefficient α is calculated to perform initial setting paper feed control. Determine the quantity H0. The paper feed amount temperature correction processing unit 12 adjusts the feed roller 2 during operation of the document reading device, for example, before starting to read the document.
Detect the temperature T near H1 = (1+β(T1 −
T0 )) H0 is calculated, and the motor 1 is driven by the obtained H1. Thereby, the feed amount of the paper 8 can be controlled with high precision without being affected by manufacturing variations in the feed roller 2 or temperature changes.

[0008]

Embodiment An embodiment of the present invention will be explained with reference to FIGS. 2 and 3. Note that the configuration of FIG. 1 is referred to as necessary. FIG. 2 is a flowchart of an embodiment of paper feed amount initial correction processing. In (1), the actual length of the paper 8 is measured and set as l. In (2), the actual paper length l is input from the console. In (3), the input actual paper length l is
Divide by the feed amount per pulse (1/240"),
Convert to raster number P0. P0 = 240/25.4·l (4) In step 4, the paper 8 is passed through the device, and the leading and trailing edges of the paper are detected by the output of the CCD 7, thereby counting the number of rasters P1 of the paper length between them. In (5), the difference between P0 and P1 ΔP=P0 - P1
seek. In (6), the temperature sensor 9 measures the reference temperature T0 at this time. In (7), find the initial correction coefficient α from ΔP/P0,
Furthermore, the pulse drive frequency Hi of motor 1 (1+α)
Find the initial setting pulse drive frequency H0 by multiplying by
Set in the device along with T0.

Next, FIG. 3 is a flowchart of an embodiment of paper feed amount temperature correction processing. In (8), the temperature sensor 9 detects the temperature T1 during operation.
Measure. In (9), from the measured temperature T1 and the previously set reference temperature T0, the temperature change amount ΔT=T0 - T1
Calculate. In (10), the temperature correction pulse drive frequency H1 is calculated from the previously set initial setting pulse drive frequency H0, the temperature correction coefficient β, and the temperature change amount ΔT. H1 = (1+β·ΔT)H0 Pulses are generated using the temperature-corrected drive frequency H1 determined in this way to drive the motor 1 in FIG.

0010

Effects of the Invention Since the present invention automatically performs initial correction, the number of man-hours conventionally required for inspecting and adjusting variations in feed rollers, etc., can be significantly reduced. In addition, by correcting the temperature of the feed roller, there is no need to use an expensive metal roller with a low coefficient of thermal expansion, which reduces the cost of the entire device.Furthermore, there is no need to use a program to correct image expansion/contraction or crop position. This saves memory resources and improves processing speed.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the basic configuration of the present invention.

FIG. 2 is a flow diagram of an embodiment of paper feed amount initial correction processing.

FIG. 3 is a flow diagram of an embodiment of paper feed amount temperature correction processing.

FIG. 4 is an explanatory diagram of the internal structure of a conventional paper conveyance type document reading device.

[Explanation of symbols]

1 Motor 2　Feed roller 3 Belt 4 Driven roller 5 Reading unit 6. Fluorescent light 7 CCD 8 Paper 9 Temperature sensor 10 Control device 11 Paper feed amount initial correction processing section 12 Paper feed amount temperature correction processing section

Claims (2)

[Claims] Claim 1: In a paper transport type document reading device that uses a feed roller to feed paper to or eject paper from the reading unit, a temperature sensor is installed near the feed roller, and the temperature sensor detects the temperature. A paper conveyance control method for a document reading device, characterized in that a paper feed control amount of a feed roller is corrected based on temperature. 2. According to claim 1, the difference between the paper feed control amount of the feed roller and the actual paper feed amount is checked in advance;
A paper conveyance control method for a document reading device, characterized in that a paper feed control amount is initially corrected.