JPH04150470A - Method for detecting black streak of scanner - Google Patents

Abstract

PURPOSE:To prevent the occurrence of such a case that a user continuously uses facsimile equipment without knowing black streaks marked on transmitted data by checking several pages of transmitting data for the black streaks and informing the user of the checked results. CONSTITUTION:In the case a CPU 5 detects black dots in a RAM 14 when data are outputted by one page, the CPU 5 increments a counter 13. When no black dot is found in the RAM 14, the CPU 5 decrements the counter 13. When the value (n) of the counter 13 becomes n=N (N: an arbitrary set value), it is discriminated that black streaks in the auxiliary scanning direction are continuously found on N pages. After discrimination, an error signal is outputted from the counter 13 to the CPU 5 and a message 'Scanner system is stained.' is displayed on a displaying section 1. Therefore, the occurrence of black streaks due to the staine of the scanner system can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a method for detecting black streaks in a scanner, which determines whether or not there are black streaks in the sub-scanning direction of the scanner section, and displays a message to the user to clean them. Regarding the method.

[Prior Art] In facsimile machines, an image reading method using COD is widely used. This method irradiates light from a light source onto the document surface, and uses an optical system such as a mirror to convert the light into CO2.
The light is focused on D. For this reason, for example, if dust adheres between the light source and the document surface, the light will be blocked by the dust, and black streaks will occur on every page in the sub-scanning direction.

Conventionally, as a method for detecting black streaks in the sub-scanning direction of a scanner, there is a method described in, for example, Japanese Patent Laid-Open No. 120579/1982 or Japanese Patent Laid-Open No. 226167/1982. In the former method, the maximum value output of white reference plane scanning is stored, and when the image signal of the document surface is read, the stored white reference value is read out and corrected. This eliminates the influence of dust, dirt, etc., and also eliminates the influence of light source. Appropriate shading correction can be applied even when the light intensity decreases. In the latter case, a line memory stores image signals for one main scanning line, and a black pixel verification circuit examines the line memory and determines that there is dirt on the reading surface when, for example, three consecutive pixels are black. and an alarm is displayed.

[Problems to be Solved by the Invention] As described above, the black streaks in the sub-scanning direction of the scanner can be detected by the user on the output paper when copying, etc.; However, if you are using a scanner, you may not be able to find it forever.

The purpose of the present invention is to solve such conventional problems and to provide a scanner that easily detects the occurrence of black streaks and notifies the user to remove dust and other contaminants from the scanner system. An object of the present invention is to provide a method for detecting black streaks.

[Means for Solving the Problems] In order to achieve the above object, the method for detecting black streaks in a scanner according to the present invention includes a RAM that holds the signal of the previous line that has been input, a signal of the current line that is being input, and a signal of the previous line that is being input. It is equipped with a circuit that calculates the negative AND of signals and a CPU that controls these, and only the signals whose matching points are black in the negative AND circuit are R
By inputting data into AM and outputting the contents of RAM to the CPU, the CPU determines whether or not there are black streaks in the sub-scanning direction within one page when the scanning operation of one page of the original is completed, and detects the black streaks. The feature is that when a predetermined number of consecutive pages with stains occur, the scanner system displays the presence of stains to the user.

[Function] In the present invention, as a black streak detection section, one line R
An AM, an AND gate, a CPU, and an error counter are provided to create a one-line RA that stores the serial image signal of the current input line from the scanner and the image signal of the previous line.
If the matching point in the sub-scanning direction is black, it is determined that a black stripe has occurred, and the error counter is incremented. Furthermore, if there is no black stripe, the error counter is decremented.

This makes it possible to detect black streaks in the scanner system using a simple method, and by displaying and informing the user of this, it is possible to have the user resend a high-quality image.

[Example] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a system block diagram of a facsimile machine to which the present invention is applied.

In Fig. 2, 1 is a display unit for displaying guidance to the user, 2 is a scanner that scans the original, 3 is a COD that collects reflected light from the original and converts it into electricity, and 4 is the previous 1.
2-line RAM for storing the current scanned line while the line is being sent out;
PU, 6 is a RAM for storing input data, etc., 7 is a ROM for storing programs, user registration destination information, etc., 8 is a plotter for printing received images or images for copying, 9 is encoding for transmission. 10 is a communication unit for transmitting facsimile information to a line, and 2o is a bus that commonly connects each circuit.

Classifying each of these devices by function, there is a display section 1 for interfacing with the operator, a communication section 10 for interfacing with the telephone line. A CCD 3, a scanner 2, 2 line RAM 4, and a plotter 8, which analyze the calligraphy information of the original into pixels and continuously convert them into electrical signals, and reproduce visible images from the electrical signals, compress the calligraphic signals in the band. , an encoding unit 9 for converting into a signal suitable for a telephone line;
CPU 5 for removing redundancy of the calligraphy signal and reproducing it
, RAM6, and ROM7.

FIG. 1 is a block diagram of a black streak detection section in the scanner 2 in FIG. 2.

In FIG. 1, 1 is a display unit, 5 is a CPU, and 11 is an AN
12 is a line counter, 13 is an error counter, 14 is a RAM for 1 line, and 15 is a serial/parallel conversion circuit.

A video signal is serially input from the left side of FIG.
Sent to 0. At this time, the negative logic AND gate 11
A video signal is also input. That is, one line of video signal currently being scanned is serially input to one of the two inputs of the AND gate 11. AND
The other input of the gate 11 receives the output of the RAM 14 for one line, that is, the video signal of 1 lines scanned last time.

If any one dot on the previous line is black (signal level is Low level) and the matching point of the current input line in the sub-scanning direction is also black, the AND gate 11 writes LOW to the RAM 14 for one line. The level is entered. The output of this one line of RAM 14 is input to the AND gate 11 and also to the CPU 5.

When data output for one page is finished, R is sent to CPU5.
If there is a black dot (low level) in the AM 14, the CPU 5 increments the error counter 13. Also, if there is no black dot, the error counter 13
Decrement.

Therefore, the value n of the error counter 13 is set to any set value N
If n=N, it is determined that there are black streaks in the sub-scanning direction for N consecutive pages. At this time, since an error signal is output from the error counter 13 to the CPU 5, the CPU 5 displays on the display section 1 that there is dirt in the scanner system. The user removes dirt by looking at this and performing maintenance.

This can prevent black streaks caused by dirt on the scanner system.

FIG. 3 is a flowchart of a black streak detection operation showing one embodiment of the present invention.

First, it is determined whether or not reading of a document has started (step 101). If it has started, a line scan is input (step 102) and the line counter 12 is turned on (step 103).

Scan input is performed sequentially and it is determined whether or not the last line has been reached (step 104). When the last line is reached, it is determined whether there is a boat input (step 105); if not, the error counter 13 is is cleared (step 107), and if there is a vote input, the error counter 13 is incremented (step 106). Next, it is determined whether the value n=N of the error counter 13 is reached (Step 108). If it is not H, the line scan input is performed by returning to the beginning (Step 102). When n=N, the contact In order to notify that there is dirt on the glass, step 109) and the display section are turned on (step 110).

In this way, black dots continue at the same position in the sub-scanning direction,
If there are black streaks for a predetermined number of pages, it is assumed that the scanner's contact glass is dirty.
Display to user.

[Effects of the Invention] As explained above, according to the present invention, black lines between several pages are checked and the user is informed of the black lines by displaying the same. The user will not continue using the facsimile without knowing it. As a result, you can always send messages with a clear screen.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a black streak detection section showing an embodiment of the present invention, FIG. 2 is a block diagram of a facsimile system to which the present invention is applied, and FIG. 3 is a flowchart of the detection operation in FIG. 1. . 1: Display section, 2: Scanner, 3: CCD14: 2-line RAM, 5: CPU, 6: RAM, 7: R
OM, 8: plotter, 9: encoding section, lO: communication section,
11: AND gate, 12 line counter, 13:
Error counter, 14:1 line RAM, 15 digit serial/parallel conversion circuit.

Claims (1)

[Claims] (1) In the scanner section of a facsimile machine, a RAM that holds the inputted previous line signal, a circuit that takes the negative AND of the current inputted line signal and the previous line signal, and a CPU that controls these. By inputting only the signal whose matching point is black in the negative AND circuit to the RAM, and outputting the contents of the RAM to the CPU, the CPU finishes scanning one page of the original. At times, it is determined whether or not there are black streaks in the sub-scanning direction within the one page, and when a predetermined number of consecutive pages with black streaks occur, the scanner system displays to the user that there is dirt on the scanner system. A method for detecting black lines using a scanner.