JPS6342277A - Image reader - Google Patents

Abstract

PURPOSE:To simplify a delay time control system required for reading the same part of an original by variably setting an interval between adjacent photosensor arrays according to a scanning speed. CONSTITUTION:A video signal read in a CCD unit has a color matching processing in a reader synchronizing circuit and video data is inputted to a variable power buffer memory and subjected to a variable power processing. In the CCD unit, 13 photosensor arrays are arranged, a green filter is covered on the array 7, a blue filter is covered on the arrays 1, 4, 5 and a red filter is covered on the arrays 9, 10, 13. In an equal power mode, the arrays 1, 7, 13 are selected at the scanning speed V, in a double mode, the arrays 4, 7, 10 are selected at the scanning speed V/2 ald the arrays 5, 7, 9 are selected at the scanning speed V/3 a triple mode. Such a selection signal is formed in an array interval control circuit 80 and the photosensor array having the interval proportional to the scanning speed is selected, thereby, the capacity of a buffer memory is made constant.

Description

[Detailed description of the invention] Technical fields> The present invention relates to an image reading device.

<Prior Art> A conventional reading device that arranges a plurality of photosensor arrays in parallel and performs mechanical scanning in a direction substantially perpendicular to the column direction of the array to extract a plurality of pieces of information in parallel has the following drawbacks. Ta.

Below, as an example of multiple pieces of information, a case will be described in which multiple colors of the same point on a document are read and output through a filter.

Alignment in the mechanical scanning direction is performed as follows for reading the same portion of the document of the photo sensor array corresponding to each color. Let the interval between the first sensor arrays corresponding to each color be respectively, and the time it takes for the image of the original to be input to the photosensor arrays corresponding to each color is /V, where the mechanical scanning speed is V. There is a gap. Therefore, the video data from the other photosensor arrays is temporarily stored in the buffer memory until the 81-point image is input to the photosensor array that is inputted temporally last.
Video data of multiple colors of point images are output together.

In this configuration, when the mechanical scanning speed V is changed for magnification change, etc., the delay time L, /V changes.
This has the disadvantage that the configuration of the delay time control system becomes complicated.

<Objective> An object of the present invention is to eliminate the drawbacks of the above-mentioned conventional example and provide an image reading device suitable for variable magnification processing.

<Embodiment> (Overview of Apparatus Mechanism) FIG. 1 is a perspective view of a digital color image forming apparatus according to an embodiment of the present invention, and FIG. 2 is a configuration diagram schematically showing FIG. 1. The present invention will be explained in detail based on FIGS. 1 and 2. An original 20 is placed on the original table glass 1 on a flat surface. The original surface of the original 20 faces the surface of the original platen glass l, and the original 20 is pressed by the pressure plate 1a. Manuscript 20
The reading head (hereinafter referred to as "reader") 3 is a reading sensor (hereinafter referred to as "CCD unit") consisting of a CCD array consisting of multiple reading elements in three rows for each of the three colors: red, green, and blue (hereinafter referred to as "R, G, and B"). 17 and
An exposure lamp 19 is placed thereon, and is connected to and driven by a main scanning motor 6a by a main scanning wire 8a. The sub-scanning table 5a supports one end of the main-scanning wire 8a, and supports the sub-scanning wire 10a.
is connected to and driven by the sub-scanning motor 9a.

A recording paper 21 is placed on a recording table 2, and a copy image is recorded by a recording head (hereinafter referred to as a printer) 4. The printer 4 prints yellow, magenta, cyan, and black (hereinafter Y, M,
C, Bk) A recording element (hereinafter referred to as a BJ head unit) 18 consisting of a multi-ink jet head for four colors (hereinafter referred to as a BJ head as a bubble jet head was used in the present invention)
is mounted, and the main scanning motor 6 is connected by the main scanning wire 8b.
b and is driven. The sub-scanning stand 5b supports one end of the main-scanning wire 8b, and is coupled to and driven by the sub-scanning motor 9b by the sub-scanning wire 10b.

When trying to obtain a copy image in the above configuration, the reader 3 is connected to the main scanning motor 6a via the main scanning wire 8a.
is driven to reciprocate in the main scanning direction.

At this time, the exposure lamp 19 is turned on and the reading sensor 17 reads the document 20 from below and outputs image information as an electrical signal. Based on this electrical signal, the printer 4 is driven by a main scanning motor 6b via a main scanning wire 8b.
Printing is performed on the recording paper 21 while reciprocating. At this time, the main scanning directions of the reading head 3 and the recording head 4 are set in opposite directions to each other in this embodiment. - After the copying process in the main scanning direction is completed and the exposure lamp 19 is turned off, the reader 3 and the printer 4 move in a direction perpendicular to the main scanning, that is, in the sub-scanning direction, to the position where the next main scanning is to be performed.

At this time, the reader 3 is driven by the sub-scanning motor 9a via the sub-scanning wire 10a together with the sub-scanning table 5a supporting the main-scanning wire 8a, moves to a predetermined position, and then stops. Further, the printer 4 is driven by a sub-scanning motor 9b via a sub-scanning wire 10b together with a sub-scanning table 5b supporting a main-scanning wire 8b, and moves to a predetermined position and then stops.

(Device Control Operation...Preliminary Operation) FIG. 3 is a block diagram of the control circuit of the above-described embodiment, FIG. 4 is a timing chart of the entire sequence, and FIG. 5 is a program flowchart.

First, an outline of the operation of the apparatus will be explained using FIGS. 4, 5, and 6. Note that the step numbers on the timing chart and flowchart are the same.

Sequence controller 23, image controller 2
4 both have a microcomputer unit in the center,
Sequence control of the apparatus and timing of image data formation are programmed in each, and both microcomputers communicate data via line 39.

To explain the sequence from power-on, the sequence controller 23 initializes the copying machine in step 1 according to the flowchart in FIG. 5, and then in step 2.
The main scanning and sub-scanning of the leader and blink are performed to return to the home position. Next, in step 3, a recovery operation of the inkjet head is performed. The head recovery operation is used to forcibly remove ink stuck to the tip of the inkjet nozzle after the device has stopped operating for a long time. This operation is performed by pressing or sliding contact with a material with good water absorption such as a porous member on the tip of the head.In terms of sequence, the printer main scanning motor 6b is rotated in the backward direction, and the recovery system position sensor 22 is activated. It is stopped by the detection output.Next, a drive mechanism such as a solenoid that presses the porous member against the head is turned on, and the porous member is pressed against the nozzle tip for a predetermined period of time.

After completion, the printer main scanning motor 7b is rotated in the forward direction and stopped by the detection output of the printer main scanning home position sensor 12.

Next, in step 4, an operation is performed to cap the head in order to prevent a change in the viscosity of the ink at the nozzle tip during a pause before the copying operation of the apparatus. This is accomplished by turning on a drive mechanism such as a solenoid that applies the cap at the home position of the printer. Next, in step 5, the operator waits for input from the operation unit 25, decodes the input data, and sets the copy mode.In step 6, it is determined whether or not it is a copy start command.If it is not a copy start command, step Returning to step 5, if copying is to be started, the process proceeds to step 7, where the cap drive of the head is released in order to start the copying operation. Next, the process advances to step 8, and a blank ejection process is performed for the head prior to the copying operation. The idle ejection process is a process that is performed to ensure stable recording.The idle ejection process is performed during the copying pause time to prevent ejection irregularities at the start of ejection for image formation caused by changes in the viscosity of the ink remaining in the inkjet nozzle. This is an operation for ejecting and discarding ink in an inkjet nozzle according to programmed conditions such as , internal temperature of the apparatus (temperature sensor not shown), and copying duration time. Next, in step 9, the original exposure lamp 19 is turned on and shading correction processing is performed. Shading correction involves reading a standard white plate that serves as a reference for white data prior to scanning the original, and sampling data for correcting aberrations of the optical system lens and sensitivity variations of each bit of the CCD sensor.

Next, the process proceeds to step 10, and it is determined whether or not it is immediately after the start of the copy start. If it is immediately after the start of copying, that is, before the start of the first main scan, the process proceeds to step 11, and if it is the second or subsequent time, the process proceeds to step 12. In step 11, a head recovery operation is performed in anticipation of a long period of suspension of the apparatus. The recovery operation in this case is the same as that described in step 3. Next, the process advances to step 12 to start main scanning.

(Refer to Figure 6 for each signal.) (Device control operation - copying) For main scanning, first, a speed data corresponding to the magnification ratio and a rotation start signal in the forward direction of the reader are sent to the motor driver circuit 26a of the reader via line 40. , and turn on the reader main scanning motor 6a. Next, after taking a synchronization delay time between the reader and printer according to the magnification ratio, line 4
1 to the motor driver circuit 26b of the printer to turn on the printer main scanning motor 6b. Main scanning motor 6a of reader and printer.

The rotation speed of 6b is determined by pulses (FG
The multiplied signal is compared with the rotational speed reference pulse by the motor driver circuits 26a and 26b, and is locked to a predetermined rotational speed by PLL control, resulting in a constant rotational speed. Further, each encoder pulse is sent to the video data synchronization signal generation circuit 28 and the head data synchronization signal generation circuit 38 via lines 42 and 43.

(Reader side processing) Next, the process advances to step 13, where a copying operation is performed.

As shown in FIG. 3, the video data synchronization signal generation circuit 28 generates position information in the reader main scanning direction in synchronization with the encoder pulse of the reader main scanning motor 6a, and the effective range of video data with a resolution l in the sub-scanning direction. The video line enable signals (hereinafter referred to as V, L, E) indicating the 6th-a,
It is made as shown in Figure 6-b. Furthermore, from the video data start signal input from the CCD drive circuit 29,
Video data enable signal (V, D, E,) that indicates the data effective width of all CCD pixels and is synchronized with the encoder pulse.
Output.

At the same time, the three rows of blue (B) and green (G) on the COD unit 17 are sent to the CCD drive circuit 29, respectively.

A CCD start signal for instructing CCDs corresponding to three colors of red (R) to read images is supplied through line 57 in synchronization with encoder pulses. The analog video signals for the three colors read in the CCD unit 17 are gain-adjusted so that the sensor sensitivity of each color is equal, and then output as digital values with 8-bit depth on line 1.
It is output through 4. At this time, the video data screen -1- signal indicating the data effective range of all pixels on the CCD is also
Output from two drive circuits. Digital video data of three colors B, G, and R (hereinafter referred to as side data) is input to a reader synchronization circuit 30.

Here, to explain the video synchronization signal generation circuit 58, the video synchronization signal generation circuit 28 receives a signal from the reader + nogist position sensor 15.
Line 45, v, r4. E, signals are counted according to the copying magnification from line 46 and image controller 24. Values of V, L, E, signals are input through line 47, respectively, to reader 1 for image alignment.
V is the time delay after the CCD unit passes through the nozzle position until it reaches the leading edge of the document, that is, the reading start position.
, L, I! : This is done by counting Shinkan.

Also, a signal video enable signal (hereinafter referred to as 1., E, signal) indicating the reading width in the main scanning direction according to the copy size.
is output and input to the reader synchronization circuit 30 via line 48.

In the reader/synchronization circuit 30, in the 6th C-dore I, when reading the same part of the document (1+, G, R each color λ, 1 corresponding CCI), If the distances between the CCDs corresponding to B, G, and R colors are I and l, respectively, then the image at position S1 of the document is input to the CCI corresponding to each color λj. tl, l is the main scanning position (if 8 degrees is V, each L 1
, /V has a time lag of -9. Therefore, the video data from CCIs B and CCI) are temporarily stored in the buffer memory in the reader/synchronizer circuit 30, until the image at point S1 of CCI), which is inputted temporally last, is input. 13. of the image of the soaked S1 point. The G and R three color video data are output from the reader synchronization circuit 30.1. Also, the signals V,
When the three color video disks are complete, output the video data area (V, D, A) signal indicating the state if: 3, and 6th-c.
The vertical direction in the figure is the time axis -C' and is not the sub-scanning direction.

The video data that has been subjected to color distortion processing in the reader/synchronization circuit is then input to a scaling buffer memory 31 where it is subjected to a first scaling process.

(variable magnification processing) Here, the scaling process will be explained using FIG. 7.

The magnification processing in the main scanning direction is performed by keeping the scanning speed v1 of the printer constant and changing the scanning speed of the reader to V l /n (n is the magnification ratio). This is because the upper limit of the driving frequency of the Infusiera I head, which is the blink image forming means, is lower than the upper limit of the driving frequency of the CCD.

Is it the same size there? When copying, the maximum inkjet driving frequency is used at the same magnification to increase the copying speed. At this time, the variable magnification mode signal is sent from the image controller 24 through line 49 in FIG. V, L, E are sent to the signal generation circuit 28.

The frequency division ratio of the reader's motor encoder pulse is set so that the signal has the same frequency when the magnification is the same and when the magnification is changed (
Figure 7-a).

That is, as shown in Figure 7-a, the motor encoder pulse φM
When is the same size, as shown in φM1 (divided into 1/6, divided into 1/2
When reducing the frequency by a factor of 1, the frequency is divided by 1/12 as shown in φM1/2, and when increasing by 2 times, the frequency is divided by 1/12 as shown in the φΔ record. Divided into 1/2.

The motor encode pulse φM is doubled when its frequency is 1722 times the same frequency, and 1/2.3 when it is twice the same frequency.
When it is doubled, it becomes 15/3, so φM+.

φM2. φM3. The frequencies of φMl/2 are actually the same frequency.

In the above variable magnification mechanism, when in 2x mode, the main scanning speed is V/2 when the main scanning speed is V in 1x mode,
Since the buffer memory required for reading the same point by the reader described above would be twice as large, in this embodiment, as shown in FIG. The buffer memory capacity is made constant by selecting a first-sensor array having a first-sensor array spacing.

Specifically, the details are as follows. Thirteen first sensor arrays A are lined up at intervals of L+/12 and numbered from 1 to 13 in the scanning direction. 7 and 1 green filter
．． 4.5 with blue filter, 9. to, 13
Add 1 software filter to each. In the same magnification mode, the photosensor array has a scanning speed of 1. 7. Select 13.

In 2x mode, the photosensor array has a scanning speed of 4. 7. Select 10. In 3x mode, the photosensor array 5. 7. Select 9. This selection signal is generated by array spacing control circuit 8o in FIG.

With the above configuration, the delay time of multiple color synchronization can be made constant.

Here, we adopted a method of having an extra photosensor array and selectively driving it according to the scanning speed, but we also have a means for translating the photosensor array with a drive source such as a motor,
A similar effect can be obtained by varying the spacing between the photosensor array columns.

Photosensor array translation distance control is produced by the photosensor array spacing control circuit of FIG.

Also, the scaling process in the sub-scanning direction is performed using the video clock φ (CLK
8) R sent from the reader synchronization circuit 30 in synchronization with
Each pixel of the G and B video signals is stored in a scaling buffer memory 31.
This is done by controlling the address increments of the variable scaling buffer memory 3I when storing the data (Fig. 7-b).

This is achieved by inputting a scaling mode signal from the image controller 24 through a line 50 to the memory control circuit 32 and increasing or decreasing the number of clock pulses of the address counter when writing to the scaling buffer memory 31 in accordance with the scaling ratio. (Figure 7-c). As a result, data of the same pixel is written to n addresses in the memory 59b in the write mode (W) of the double buffer memories 59a and 59b in the variable magnification buffer memory 31 when enlarged by n times.
When reduced by 1/n, one pixel out of n pixels will be written to one address, and when the read mode is entered, when the address is incremented by the video clock φ-CLK8, the pixel data will be interpolated. , thinning will be achieved.

Effects> As explained above, an image reading device that extracts multiple pieces of information in parallel has a means for variably setting the distance between adjacent photosensor arrays in accordance with the speed of movement and scanning, so that the same portion of a document can be read. It has become possible to simplify the delay time control system required for reading.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an apparatus according to an embodiment of the present invention, FIG. 2 is a schematic perspective view of an apparatus according to an embodiment of the present invention, FIG. 3 is a block diagram of a control circuit according to an embodiment of the present invention, and FIG. 4 is a sequence diagram. Timing chart diagram, Figure 5 is a sequence flowchart diagram,
Figure 6-a is a diagram showing the relationship between the reader's document and the reading synchronization signal, Figure 6-b is an enlarged view of part A in Figure 6-a, and Figure 6-c is due to positional deviation of the reading CCD of each color. Explanatory diagram, No. 6-d
The figure shows the relationship between copy paper and the recording synchronization signal, Figure 6-e is an enlarged view of part B in Figure 6-d, Figure 6-f is an explanatory diagram of the positional deviation of each color inkjet head, and Figure 7- Figure a is an explanatory diagram of the interpolation and thinning operations mainly for the leader, and Figures 7-c are the diagrams for the third
FIG. 8 is a detailed circuit diagram of the variable magnification buffer memory 3I shown in the figure, and is a diagram showing a plurality of photosensor arrays.

Claims (2)

[Claims] (1) In an image reading device in which a plurality of photosensor arrays having a plurality of reading pixels are arranged in parallel, movement scanning is performed in a direction substantially perpendicular to the arrangement direction of the reading pixels, and a plurality of image information is extracted in parallel, the movement An image reading device comprising means for variably setting an interval between adjacent photosensor arrays according to a scanning speed. (2) The image reading device according to claim 1, wherein the speed of the moving scan and the distance between adjacent photosensor arrays are proportional to each other.