JPH01250940A - Image processor - Google Patents

Abstract

PURPOSE:To improve throughput by detecting the density of an original, which is carried onto an exposure plane, in a carrying path, correcting the amount of light for an exposure lamp, untile the original is positioned on the exposure plane, and correcting the level of an original density sensor when the original is not in the carrying path. CONSTITUTION:The density of the original, which is carried onto a platen glass 12 by means of an original carrying means, is detected in the carrying path I(a), and then an appropriate amount of exposure is calculated based on the detected density. Untile the original is positioned on the platen glass 12, the amount of light for the exposure lamp is corrected based on the appropriate amount of exposure which has been previously calculated. When the original is not in the carrying path I(a), the level of the original density sensor is corrected. Thus, the density of the original is accurately detected even in case the sensor drifts due to a temperature or dirt such as paper chip is produced; and the throughput is improved.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an image processing device.

(Prior Art) Conventionally, image processing apparatuses, in particular, have a function of conveying an original onto a platen glass, automatically detecting the density of an image of an original, etc., and changing the light intensity of an exposure lamp of a scanning optical system. For those that have a so-called HE function that adjusts the density, after the document is conveyed and stopped on the platen glass, the scanning optical system is pre-scanned to sample the HE data, and the exposure is performed based on the sampled HE data. The amount of light from the lamp was varied, and then another scan was performed to read the image.

[Problem to be solved by the invention]

Conventional image processing devices stop the original on a platen glass and then perform a bliscan to sample the revised data and a scan to read the image, which has a limit to throughput, and it is difficult to improve throughput. The problem was that it couldn't be done.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image processing apparatus that can improve throughput.

Another object of the present invention is to provide an image processing apparatus that can prevent sensitivity changes caused by temperature of a document density sensor and level shifts caused by paper dust.

[Means to solve the problem]

The present invention includes a document conveying means for conveying the document onto an exposure surface;
An original density detection means detects the density of the original transported by the original transporting means within the transport path, an exposure amount calculation means calculates the appropriate exposure amount based on the detected density, and A light amount correction means for correcting the light amount of the exposure lamp based on the calculated appropriate exposure amount until the document is aligned; and an original density sensor level correction means for correcting the document density sensor level when the document is not on the transport path. It is characterized by having the following.

[Effect]

In the present invention, the density of the document conveyed onto the exposure surface by the document conveyance means is detected by the document density detection means within the conveyance path, and the appropriate exposure amount is calculated by the exposure amount calculation means based on the detected density. , until the document is aligned on the exposure surface, the exposure lamp light amount is corrected by the light amount correction means based on the calculated appropriate exposure amount, and when the document is not in the transport path, the document density sensor level is corrected. Correction is performed by the density sensor level correction means.

〔Example〕

1 to 5 show one embodiment of the present invention.

This embodiment uses a circulating document feeder (hereinafter referred to as RDF).
This is an example in which the present invention is applied to an image recording apparatus having the following.

(Main body 100) The main body 100 has an image reading function and an image recording function.

In FIG. 2, reference numeral 101 is an original table glass on which an original is placed, 103 is an exposure lamp that illuminates the original, and 105.107
, 109 are scanning reflecting mirrors (scanning mirrors) that change the optical path of reflected light from the original, 111 is a lens having focusing and variable magnification functions, and 113 is a fourth reflecting mirror (scanning mirror) that changes the optical path. be. 115 is an optical system motor that drives the optical system, 117 is an image tip sensor, and 119 is a home position sensor.

131 is a photosensitive drum, 133 is a main motor that drives the photosensitive drum 131, 135 is a high voltage unit, 137 is a blank exposure unit, 139 is a developing device, 141 is a transfer charger, 143 is a separating body electrical device, and 145 is a cleaning device. .

151 is the upper cassette, 153 is the lower cassette, 155
157 is a paper feed roller, and 159 is a registration roller. 161 is a conveyor belt that conveys the sheet on which an image has been recorded to the fixing side, and 163 is a fixing device that fixes the conveyed sheet by thermocompression bonding.

The surface of the photosensitive drum 131 described above is made of a seamless photoconductor using a photoconductor and a conductor.
1 is rotatably supported by a shaft, and starts rotating in the direction of the arrow in FIG. 2 by a main motor 133 that is activated in response to pressing a copy start key, which will be described later.

Next, when the predetermined rotational control and potential control processing (preprocessing) of the photosensitive drum 131 are completed, the original placed on the original platen glass 101 is illuminated by the exposure lamp 103 configured integrally with the first scanning mirror 105. , the reflected light from the original is transmitted to the first scanning mirror 105, the second scanning mirror 107,
An image is formed on the photosensitive drum 131 via the third scanning mirror 109, the lens 111, and the fourth scanning mirror 113.

The photosensitive drum 131 is corona charged by a high voltage unit 135. Thereafter, the image (original image) irradiated by the exposure lamp 103 is exposed to slit light, and an electrostatic latent image is formed on the photosensitive drum 131 using a known NP method.

Next, the electrostatic latent image on the photosensitive drum 131 is transferred to a developing device 139.
The toner image is developed by a developing roller 140 and visualized as a toner image, and the toner image is transferred onto a sheet by a transfer charger 141 as described later.

That is, the upper cassette 151 or the lower cassette 15
The sheets in 3 are placed on paper feed roller 155 or paper feed roller 1.
57 into the main unit, and the registration roller 159
The latent image is sent toward the photosensitive drum 131 with more accurate timing, and the leading edge of the latent image is aligned with the leading edge of the sheet.

Thereafter, the sheet passes between the transfer charger 141 and the photosensitive drum 131, so that the toner image on the photosensitive drum 131 is transferred onto the sheet.

After this transfer is completed, the sheet is separated from the photosensitive drum 131 by a separation charger 143, guided to a fixing device 163 by a conveyor belt 161, and fixed by pressure and heat.
Thereafter, the paper is discharged out of the main body 100 by the discharge roller 165.

After the transfer, the photosensitive drum 131 continues to rotate, and its surface is cleaned by a cleaning device 145 composed of a cleaning roller and an elastic plate.

(RDF200) FIG. 3 shows a schematic configuration of the RDF 200 shown in FIG. 2.

In Fig. 3, 1 is a document placement table, 2 is a feed belt drive shaft, and 2a is a paper feed belt driven shaft, between which a paper feed belt 3 is placed and rotates in the direction of arrow C in the figure. .

4 is a separation belt drive shaft, 4a is a separation belt driven shaft, between which the separation belt 5 is placed, and rotates in the direction of the arrow in the figure. 2b is a half-moon-shaped roller that rotates in the direction of arrow E in the figure. Feeding - The paper belt 3, the separation belt 5, and the half-moon roller 2b separate a plurality of sheet-shaped originals placed on the original placing table 1 one by one starting from the bottom.

6 is a conveyance roller, and 6a and 6b are rollers that are in pressure contact with the conveyance roller 6, respectively. 9.10.11 is a conveyance roller,
9a, 10a, and lla are conveyance rollers 9.
This is a roller that comes into pressure contact with 1O111.

7 is a platen glass 1 installed on the top plate of the copying machine main body M.
Conveyor belt drive roller 7a located near the left side of 2
is a conveyor belt driven roller located near the right side of the platen glass (exposure surface) 12, and between them, in the direction of arrow a,
Alternatively, the conveyor belt 8 rotating in the direction indicated by the arrow is out of order.

The lower surface of the conveyor belt 8 faces or contacts the upper surface of the platen glass 12 in close proximity.

Further, reference numerals 13 to 17 are reflective optical sensors that detect the leading edge or trailing edge of a document, which are disposed at predetermined locations on the document circulation path (paper path).

Sensors 13 and 14 are a paper feed sensor and a paper feed registration sensor, respectively.

Reference numeral 20 denotes a reflective optical sensor (ES) that detects the original placed on the original platen 1; 19 a recycle sensor (R5) that detects one circulation of the original bundle; At that point, the recycle sensor (R5) 19 is turned on, and the document is fed separately from the bottom document, and when the rear end of the final document passes through the partition arm 22, the partition The arm 22 is designed to pass through the recycle sensor (R5) 19 due to its own weight and be turned off.

FIG. 4 shows the drive section. In FIG. 4, 80 is a motor (M2), 81 is a motor gear, and transmits driving force to the paper feed belt drive shaft 2, separation belt drive shaft 4, and half-moon roller 2b through a gear 96. 82 is a belt drive motor (M
1), 83 is a motor pulley, and 86 is a two-stage pulley, which transmits the drive force from the heald 87 to the belt 88.

The pulley 89 is also a two-stage pulley, and transmits the driving force from the belt 88 to the belt 90, thereby constantly transmitting the driving force to the drive roller 7 of the conveyor belt 8 through the pulley 91.

Reference numeral 93 designates a disc having a notched groove 94 that rotates integrally with the two-stage pulley 89, and allows a photoelectric sensor 95 to detect the amount of movement of the belt 8. Reference numeral 92 denotes an electromagnetic brake (on B) which, when turned on, makes it possible to stop the heald 8 instantly.

97 is a conveyor motor (M3), 98 is a gear, 99 is a pulley, and 100, 101, 101', and 102 transmit driving force to belt conveyor rollers 6.9.10.11.

Reference numeral 103 denotes a disc with a notched groove 104 that is rotated integrally with the pulley 99, and is detected by a photoelectric sensor 205 as a transport roller 6.9.
．． The rotation amount of 10.11 can be detected, that is, the amount of conveyance movement of the document can be detected.

23 is a switching claw, and the platen glass 12 is moved by the fulcrum 106.
A tension spring 24 and a solenoid (SL) 207 are used to switch between transporting the upper document toward the transport roller 6 or from the transport roller 9 toward the platen glass 12.

Next, document feeding by RDF200 when copying a one-sided document,
Explain the paper movement.

First, as shown in FIG. 3, a plurality of sheet-like single-sided originals with the same page order are placed on the original table 1 with the first page facing upward.

The placed original is transported to one place by the paper feed belt 3 and separation belt 5.
The originals are separated and fed sheet by sheet from the bottom, and the fed documents pass through the paper path Ia and are transferred to the platen glass 1 by the conveyor belt 8.
2, the original is sent out with the image side facing downward.

When the trailing edge of the document is detected by the sensor (S2) 14, counting of the number of notched grooves 94 in the disk 93 (FIG. 4) is started from that point on, and after counting a predetermined count, the motor (Ml) 82 is turned off, and the electromagnetic brake (BK) 92 is turned on, and the rotational drive of the conveyor belt 8 is instantly stopped. As a result, the document is automatically positioned and set at a predetermined position on the surface of the platen glass 12.

When the document is positioned on the platen glass 12 in this manner, the copying operation is started, one exposure scan is performed, and the copied copy paper is stored in the paper discharge tray. After the exposure of the original is completed, the solenoid (SL) 207 is turned on, the switching claw is in the state shown by the broken line, and the exposed original is transferred to the paper bus l1.
la and is discharged through IVa. At the same time, the next original is fed in parallel by the above-described operation and positioned and set on the platen glass 12.

This parallel operation is simply an operation of circulating the original, and along the way,
Since the inversion of the original is not performed for the previous or next original, this operation is called normal discharge and normal feeding operation. Then, normal feeding and discharging operations are sequentially performed, one circulation of the set original is detected by the recycling sensor (R5) 19, and the end of the circulation is sent to the copying machine main body M, and the number of copies is counted. The above operation is repeated until the set number of copies is reached, and the required number of copies is stored in the output tray of the copying machine.

Note that the RDF 200 has a circulation function that supports double-sided originals, but a description of this function will be omitted since it is not directly related to the purpose of the present invention.

FIG. 1 shows a control device 300. FIG.

Components similar to those in FIGS. 2 to 4 are designated by the same reference numerals. In the figure, 25-1 is an AE lamp as an AE light source, and 25-2 is a meter sensor (reflection type sensor), each of which is provided outside the conveyance path Ia. Said AE lamp 25-
1. The E sensor 25-2 constitutes a document density detection means, and detects the density of the document being conveyed within the conveyance path.

A specific example is shown in FIG.

Reference numeral 24 denotes a standard white plate, which faces the AE sensor 25-2 and is used to correct the white level of the AE sensor 25-2. 301 is a central processing unit (CPU
), for example, a microcomputer μC0M8780 manufactured by NEC (NEC Corporation) is used as an exposure amount calculation means to calculate an appropriate exposure amount based on the detected document density. In addition, the CPO 301 functions as a document density sensor level correction means, and when the document is not on the conveyance path, the AE
This is to correct the sensor level.

302-1 is a read-only memory (ROM) in which a control procedure (control program) as shown in FIG. 6 according to the present invention is stored in advance;
Each component device connected via the path is controlled according to the control procedure stored in the path. 302-2 is a random access memory (RAM) which is a main storage device used for storing input data and as a working storage area.

An interface (Ilo) 303 outputs a control signal of the CPU 301 to a load such as the optical system motor 115. 304 is an interface, which is the image tip sensor 1;
17 or the like is manually sent to the CPU 301. 305 is an interface connected to a load such as the transport motor 97 of the RDF 200, and 306 is a paper feed sensor 13.
etc., 3o7 is the AE sensor 2
Analog data from 5-2 is A/D converted and CPt1
7) A/D converter. Reference numeral 308 constitutes a light amount correction means together with the CVR and CPU 301, and the CPU 3
The exposure lamp light amount is corrected based on the appropriate exposure amount calculated by 01.

FIG. 6 shows an example of a control procedure stored in the ROM 302-1.

First, in step Sl, it is checked whether or not a stack of documents is set on the document tray. If there is a document, the AE sensor 25
-2 initial data retrieval is performed. Turn off the E lamp 25-1 in step S2, and turn off the AE of that 0 temple in step S3.
The sensor data is stored in RAM302-2 (DATAB
). This is black level data. Next, in step S4, the AE clamp 5-1 is turned on, and in step S5, the AE sensor data at that time is stored in the RAM 302-2.
Store it in (DATAw) inside. This means that white level data is stored by reading the white plate 24 on the opposite surface of the AE sensor 25-2.

Then, in step S6, separation is started by turning on the copy key of the copying machine, and the originals are separated one by one from the bottom. When the leading edge of the document reaches the paper feed sensor 13 in step S7, conveyance is started in step S8. At the same time, the ■ lamp 25-1 is turned on, and in step S9, the data of the AE sensor 25-2 at that time, that is, the E sensor data corresponding to the document density is stored in the RAM 302-2 (
DATAs). In the tree embodiment, only one point is sampled, but accuracy can be increased by sampling multiple times and taking the average.

Then, in step 510, (DATAw), (DATAB), (
DATAS) calculates the AE data. This is, for example, (DATAw) J , OV, (DATA
a) When -4,2V (DATAs) -2,5V, (2,5-1,0)/(4,2-1,0)-4
The density becomes 1, and this value causes the AE to be set in step Sll.
It is good to correct the light amount of the clamp 5-1. Then, in step 512, the trailing edge of the document is detected by the paper feed registration sensor 1.
4, starts a registration count of a predetermined value in step S13, waits for the count to be counted by the belt crotter in step 514, and waits for the count to increase.In step 515, the conveyance of the document is stopped, and the document is placed in a predetermined position on the platen glass. At step 516, the optical system is started and image reading is started.

FIG. 7 shows an example of the AE data described above.

Generally, when changing the light intensity by correcting the light intensity of a lamp, either a delay time is required depending on the characteristics of the lamp, or the correction started in step Sll is sufficient to cover the document transport time from step 512 to step 515. The amount of light is completely corrected at the start of reading in step 316. Furthermore, by correcting the daytime sensor data each time before sending the document, the density of the document can be accurately detected even if there is a temperature drift of the meter sensor 25-2 or dirt such as paper dust.

〔Effect of the invention〕

As explained above, since the present invention is constructed as described above, there is an effect that the throughput can be improved.

Moreover, in the present invention, when the document is not on the conveyance path,
Since the original density sensor level is corrected, sensitivity changes due to temperature and level shifts due to paper dust can be prevented.

[Brief explanation of the drawing]

1 to 5 are views showing one embodiment of the present invention, in which FIG. 1 is a block diagram showing a control device, FIG. 2 is a sectional view of an image recording device, and FIG. 4 is a sectional view showing the drive section, FIG. 5 is a circuit diagram showing the E sensor to the AE clamp shown in FIG. 1, and FIG. A flowchart showing an example of a control program stored in the illustrated control device, and FIG. 7 is a diagram showing an example of AE data used in the control program illustrated in FIG. 6. 25-1... AE lamp, 25-2... AE sensor, 200... Circulating document feeder, 301.
... central processing unit, 308 ・CVR. 24th V 5th■

Claims (1)

[Scope of Claims] 1) An original transport means for transporting the original onto the exposure surface, an original density detection means for detecting the density of the original transported by the original transport means within the transport path, and an original density detecting means for detecting the density of the original transported by the original transport means, an exposure amount calculation means for calculating an appropriate exposure amount based on the exposure amount; a light amount correction means for correcting the exposure lamp light amount based on the calculated appropriate exposure amount until the original is aligned on the exposure surface; An image processing apparatus comprising: an original density sensor level correction means for correcting the original density sensor level when the original density sensor level is not equal to the original density sensor level.