JPH0323764A - Image reader - Google Patents

Abstract

PURPOSE:To inform the staind state of platen glass hard to recognize to an operator by discriminating the stained state of the platen glass by comparing an image state decided with sampled image information with the image state set as reference decided in advance, and issuing an alarm. CONSTITUTION:A sampling means 4 obtains the image information of an article 3 to be read at a state where the article 3 to be read with prescribed density is placed on the platen glass 1. Then, the image state decided with the image information obtained with the sampling means 4 is compared with the image state set as reference decided in advance, and a stain judging means 5 judges the stained state of the platen glass 1. An alarm means 6 issues the alarm based on a judged result at the stain judging means 5. The operator, when recognizing a stain on the platen glass 1 based on the alarm from the alarm means 6, cleans up the platen glass 1, and after that, performs regular duplication. ln such a way, it is possible to inform the stained state of the platen glass hard to recognize to the operator in advance.

Description

[Detailed Description of the Invention] [Summary] Regarding an image reading device that optically scans a document placed on a platen glass to read image information, an image reading device that notifies an operator of the difficult-to-understand dirt condition on the platen glass in advance. The object of the present invention is to provide an image reading device that prevents the reading of images in a dirty state. , a dirt determining means for determining the state of dirt on the platen glass by comparing image information serving as a predetermined standard with an image state determined from the image information obtained by the sampling means; The apparatus is constructed to include an alarm means for issuing an alarm.

(Industrial Application Field) The present invention relates to an image reading device applied to an electrophotographic copying machine, a type of facsimile machine, an image reader, etc. The present invention relates to an image reading device that scans images to read image information.

[Conventional technology]

For example, an image reading system in an electrophotographic copying machine has conventionally scanned a document placed on a platen glass sequentially while irradiating a slit light from below the platen glass. The reflected light image on the original is read and imaged as image information on a photoreceptor that is in a charged state. In addition, in a so-called digital copying machine, the reflected light image obtained as described above is converted into an electrical signal by an image sensor such as a COD, and the signal modulates a laser beam on the photoconductor, which becomes a charged state. I'm writing a light image on it. Then, through various processes such as toner development corresponding to the electrostatic transfer image formed on the photoreceptor in response to these light images, furthermore, the toner image is transferred to recording paper, image fixation, etc., and then the original is printed. The image drawn on the image is reproduced on recording paper (copying).

(Problem to be Solved by the Invention) In this type of conventional image reading device, such as the image reading system in the above-mentioned copying machine, when the top of the platen glass is dirty, it is impossible to prevent the image from being read in that dirty state. It was difficult to do so.

This is because stains on the platen glass are relatively difficult to detect. In the case of copying machines, etc., it is common to notice stains on the finished document after actually making copies, and especially when making large quantities of copies using an automatic document feeder, paper and time-consuming The amount of waste can become enormous.

Therefore, an object of the present invention is to notify the operator in advance of the difficult-to-understand state of dirt on the platen glass.

? Means for Solving the Problems) The present invention is based on (1) an image reading device that optically scans a document 2 placed on a platen glass 1 to read image information, and the image reading device solves the above problems. As shown in FIG. 1, technical means for solving the problem include a sampling means 4 that obtains image information with an object 3 of a predetermined density placed on a platen glass 1, and a predetermined standard. A dirt determining means 5 determines the state of dirt on the platen glass 1 by comparing the image state determined by the image information obtained by the sampling means 4 with the image state determined from the image information obtained by the sampling means 4; It is equipped with 1,000 alarm stages 6 for issuing an alarm.

The object 3 to be read having the predetermined density may be prepared using a platen cover (usually white inside) that presses the original 1 from above, or may be prepared separately as a reference. However, the mode of using a platen cover is preferable in that there is no need to prepare anything separately.

The image condition that serves as the predetermined standard is determined experimentally as being free of dirt, and specifically, the image condition is based on the grayscale image data itself, or information on the proportion of the "'black゜" (stain) area. etc. shall be determined as appropriate.

(Function) With the object 3 to be read having a predetermined density placed on the platen glass 1, the sampling means 4 obtains image information thereof. Then, the dirt determination means 5 determines the dirt state of the platen glass 1 by comparing the image state determined from the image information obtained by the sampling means 4 with a predetermined reference image state. Then, the alarm means 6 issues an alarm based on the judgment result of the dirt judgment means 5.

When the operator detects dirt on the platen glass 1 due to the alarm from the alarm means 6, the operator can clean the platen glass 1.
After cleaning, the official copy is made.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 2 is a diagram showing an example of the structure of a copying machine to which an image reading device according to the present invention is applied. This copying machine is of an electrophotographic type, and its scanning system is of a moving platen type.

In the figure, reference numeral 10 indicates an original to be copied, and reference numeral 11 indicates a platen glass 14 on which the original 10 is placed, a platen cover that holds down the original 10. As shown in FIG. When scanning a document, the platen glass 11, the document 10, and the platen cover 14 move together horizontally in the direction indicated by the arrow. A light source lamp 12 and a self-cleaning lens 13 are arranged below the platen glass 11, and the light emitted from the light source lamp 12 is reflected on the surface of the document 10 that moves as described above, and the reflected light image is self-cleaning. The image is formed through a lens 13 on a photosensitive drum 20 that rotates in synchronization with the movement of the document 10. A charger 21 is installed around the photosensitive drum 20 on the upstream side of the image forming position to perform an electrophotographic image forming process.
, a toner developing device 22 and a transfer device 23 are arranged on the downstream side. Then, a toner image corresponding to the optical image formed on the photosensitive drum 20 is transferred onto the recording sheet 26 by the charging action of the transfer device 23, and then the image is fixed by the fixing device 24. There is.

The light source lamp 12 and self-cleaning lens 13 are housed within a cover 15 to prevent light leakage. Furthermore, a cleaner 25 for removing residual toner on the photosensitive drum 20 is provided downstream of the transfer position of the photosensitive drum 20 .

In an electrophotographic copying machine having the above-described structure, for example, an L-dimensional C
An image reading sensor 30 such as an OD array sensor is provided, and an optical path is set so that light reflected from the 1°O surface of the document via the platen glass 11 is incident on the image reading sensor 30. FIG. 3 is a block diagram showing an example of the basic structure of the control system.

In the figure, reference numeral 40 denotes a control unit that performs overall control of the entire system, and a reading signal from the image reading resensor 30 and an operation signal of a check switch 31, which will be described later, are input to this 40.

41 is a memory (RAM) that stores the read signal from the image reading sensor 30 as image information, 42 is a memory (RAM) that stores image information in a predetermined reference state, and 43 is a comparison device that compares the contents of each memory 41 and 42. Department. Then, the comparison unit 43 compares the read image information with the image information in the reference state and determines whether the platen glass 11 is dirty if noise that is not present in the image information in the reference state is present in the read image information at a predetermined number or more. It is designed to output a signal. Reference numeral 45 denotes a display made of liquid crystal or the like, and this display 45 displays an alarm based on a command from the control section 40 when the dirt determination signal is output from the comparison section 43.

The check switch 31 is a switch operated by the operator when determining whether the platen glass 11 is dirty, and is provided, for example, on the frame of the Braden glass 11, as shown in FIG. 4, together with the display 45. .

Furthermore, upon input of an operation signal from the check switch 31, the control section 40 starts up the scanning drive system 50.

In the above arrangement, the platen glass 11 is checked for dirt as follows.

First, with the platen glass 11 cleaned in advance, the original 1
0 is not set, cover the platen cover 14 (object to be copied with a predetermined density), and operate the check switch 31.

Then, image information in a clean state is stored in the memory 42. This operation is performed as an initial setting, for example, periodically.

Normally, when an operator checks the platen glass 11 for dirt before making copies, he operates the check switch 31 with only the platen cover 14 covered before operating the start switch. Then, the scanning system moves, and in the process, image information based on the read signal from the image reading sensor 30 is sequentially stored in the memory 41.

Then, when the entire surface of the platen glass 11 has been scanned,
A comparison unit 43 compares the contents of the memories 41 and 42 at that time. At this time, the noise that is not present in the reference image information stored in the memory 42 is present in the memory 42 that has just been sampled.
When the image information in 1 is included in more than a predetermined location,
The comparator 43 outputs a dirt determination signal. As a result, a warning regarding dirt is displayed on the display 45.

When the alarm is displayed on the display 45, the operator cleans the platen glass 11 and then performs a normal copying operation. Thereby, it is possible to prevent scoby from occurring on the platen glass 11 due to dirt.

In the above embodiment, a moving platen type copying machine in which the platen glass 11 itself moves is used as an example, but the present invention is of course applicable to a fixed platen type copying machine as shown in FIG. 4, for example. .

This platen fixed type copier has one platen glass
A light source lamp 12 and a shutter 16, which are arranged below the document 1, move, and in the process, light reflected from the surface of the original 10 is guided to the photosensitive drum 20 via the shutters 16 and 17. In this case, the image reading sensor 30 may be provided inside the cover 15 housing the light source lamp 12, etc.;
The roller 17 may be constructed as a half roller and may be provided on the rear side thereof.

Furthermore, image reading sensors (COD array sensors, etc.) are used in digital copying machines, facsimile machines, image readers, etc.
However, in this case, the sensor is replaced with a reading sensor for detecting dirt on the platen glass (
It can be used in common as the sensor 30) in the embodiment.

Although the comparative judgment in the comparison unit 43 is a comparison of image information, it is not limited to this, and for example, it is also possible to compare the proportion of the "black" area to determine the dirt state. be.

In addition to the display as in the above-mentioned embodiment, the warning means may be a warning sound, or may be a warning means by stopping the operation of the device.

It is also possible to judge the sampling condition step by step using an appropriate threshold value (reference condition) and display the degree of contamination on the display, such as ゜゛Very dirty''゜゜゜゜゛Slightly dirty'' It is. Sampling of image information can be performed not only with the platen cover on, but also with a sheet of standard density (for example, white) placed thereon.

(Effects of the Invention) As explained above, according to the present invention, image information is sampled with an object to be read having a predetermined density placed on a platen glass, and the image state determined by the sampled image information is determined. Since the state of dirt on the platen glass is determined by comparing it with a predetermined standard image state and an alarm is issued, it is possible to notify the operator in advance of the state of dirt on the platen glass, which is difficult to understand.

As a result, it is possible to prevent an image from being read in a dirty state, and it is possible to obtain a read image of higher quality.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the structure of the present invention, Fig. 2 is an example showing the structure of a copying machine to which the image reading device according to the invention is applied, and Fig. 3 is a reference structure example of the control system. Block Diagram,
Figure 4 is a diagram showing an example of the arrangement of check switches and indicators;
FIG. 5 is a diagram showing another example of the structure of the copying machine. l, 11...Platen glass 2, 10...Original 3...Object to be read 4...Sampling means 5...Dirty discrimination means 6...Alarm means 14...Platen cover 30...・Image reading sensor 31...Check switch 40...Control unit 41.42...Memory 43...Comparison unit 45...Display device Figure 2 Akira Kinuma ＼ 1 tusk, 1 quart 7, 11 wi Reij Mu P article /I toad, ne, 4 nose IP4A ke 11 blue, 11
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1 Io Cll 5 WI Yumi Sanito Sho Jing Arishosho (Method) September 28, Heibō 1

Claims (1)

[Claims] In an image reading device that reads image information by optically scanning a document (2) placed on a platen glass (1), an object to be read (of a predetermined density) is placed on the platen glass (1). 3) sampling means (4) for obtaining image information in a state where the
), the predetermined standard image condition and sampling means (4)
) for determining the state of dirt on the platen glass (1) by comparing it with the image state determined from the image information obtained in An image reading device comprising: warning means (6) for issuing a warning.