JP2001184486A - Device and method for forming image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and a method for forming image in sheet through system, with which an influence caused by dirt such as dust stuck on contact glass can be reduced when reading the image of an original. SOLUTION: After an optical scan unit is moved to a sheet through reading position (step S1005), when the magnification/reduction power of the original is of <=100% (YES in step S1008), the image of the original is read after moving the optical scan unit oppositely to an original feeding direction at an original feeding speed set lower than an original feeding speed determined by the power just for the moving speed of the optical scan unti. When the magnification/ reduction power of the original exceeds 100% (NO in step S1008), the image of the original is read after moving the optical scan unit in the same direction as the original feeding direction at an original feeding speed set higher than the original feeding speed determined by the power just for the moving speed of the optical scan unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus and an image forming method, and more particularly to a sheet-through type image forming apparatus and an image forming method for reading an image while conveying an original by an original conveying apparatus.

[0002]

2. Description of the Related Art In a conventional sheet-through type image forming apparatus, an image reading section arranged below a contact glass irradiates a fixed position of the contact glass with a stopped illumination lamp, and a document conveying device. The image of the document conveyed on the contact glass was read.

[0003]

However, in the conventional sheet-through type image forming apparatus, when dust or the like adheres to the fixed position of the contact glass exposed by the illumination lamp, the light of the illumination lamp emits light. Blocked by dust,
There was a case where the image of the document could not be read correctly. For example, erroneous copying occurs where a position that is not present in the original but is always readable in the width direction of the original occurs, and a linear image is formed from one end to the other in the original feeding direction.

An object of the present invention is to provide a sheet-through type image forming apparatus and an image forming method which can reduce the influence of dirt such as dust adhering to a contact glass when reading an image on a document. .

[0005]

According to a first aspect of the present invention, there is provided an image forming apparatus, comprising: a document conveying means for conveying a document onto a document table; An image forming apparatus comprising: image information reading means arranged at a predetermined position to read image information of a document; and forming an image by enlarging / reducing the image information read by the image information reading means at a predetermined magnification. At
A moving unit that moves the image information reading unit from the predetermined position at a predetermined moving speed in a predetermined moving direction, a conveying speed setting unit that sets a conveying speed of the original by the original conveying unit, A moving direction setting means for setting the predetermined moving direction of the image information reading means; and the image information reading means being conveyed at the conveying speed while moving the image information reading means in the predetermined moving direction at the predetermined moving speed. And control means for controlling to read image information of the original.

[0006] The image forming apparatus according to the second aspect is the first aspect.
In the above-described image forming apparatus, the transport speed setting unit sets the transport speed based on the predetermined magnification.

[0007] The image forming apparatus according to the third aspect is the second aspect.
In the image forming apparatus described above, when the predetermined magnification exceeds 100%, the conveyance speed setting unit sets the conveyance speed to be higher by the predetermined moving speed, and when the predetermined magnification is 100% or less, The transport speed is set to be lower by the predetermined moving speed.

[0008] The image forming apparatus according to the fourth aspect is the first aspect.
The image forming apparatus according to any one of claims 1 to 3,
The moving direction setting means sets the predetermined moving speed based on the predetermined magnification.

The image forming apparatus according to the fifth aspect is the fourth aspect.
In the image forming apparatus described above, when the predetermined magnification exceeds 100%, the moving direction setting means sets the predetermined moving direction to the same direction as the document conveying direction, and the predetermined magnification is set to 100%. In the following case, the predetermined moving direction is set in a direction opposite to the document conveying direction.

[0010] The image forming apparatus according to the sixth aspect is the first aspect.
In the above-described image forming apparatus, the moving direction setting unit sets the predetermined moving speed based on the number of documents.

According to a seventh aspect of the present invention, there is provided the image forming apparatus according to the sixth aspect.
In the above image forming apparatus, the moving direction setting unit changes the predetermined moving direction each time the document is read.

[0012] The image forming apparatus according to the eighth aspect is the seventh aspect.
In the image forming apparatus described above, the moving direction setting means sets the predetermined moving direction to the same direction as the conveying direction of the document when the document is an odd numbered sheet, and when the document is not an odd numbered sheet. The predetermined moving direction is set in a direction opposite to a direction in which the document is transported.

[0013] The image forming apparatus according to the ninth aspect is the sixth aspect.
The image forming apparatus according to any one of claims 1 to 8,
The transport speed setting means sets the transport speed based on the number of documents.

According to a tenth aspect of the present invention, in the image forming apparatus according to the ninth aspect, when the number of the originals is an odd number, the conveying speed setting means sets the conveying speed to the predetermined moving speed. When the document is set to be large and the document is not an odd number, the transport speed is set to be smaller by the predetermined moving speed.

According to an eleventh aspect of the present invention, in the image forming apparatus according to any one of the first to tenth aspects, the predetermined moving speed is lower than the transport speed.

According to another aspect of the present invention, there is provided an image forming method, comprising: image information reading means arranged at a predetermined position to read image information of a document conveyed on a document table; In an image forming method of an image forming apparatus for forming an image by enlarging / reducing the image information read by the image information reading means at a predetermined magnification, the image information reading means is moved from the predetermined position at a predetermined moving speed. A moving step of moving in the moving direction, a conveying speed setting step of setting the conveying speed of the document, and a moving direction setting step of setting the predetermined moving direction of the image information reading means,
A control step of controlling the image information reading unit to read image information of the document conveyed at the conveyance speed while moving the image information reading unit at the predetermined movement speed in the set predetermined movement direction. It is characterized by.

According to a thirteenth aspect of the present invention, in the image forming method of the twelfth aspect, the transport speed is set at the predetermined magnification in the transport speed setting step.

According to a fourteenth aspect of the present invention, in the image forming method according to the thirteenth aspect, when the predetermined magnification exceeds 100% in the conveying speed setting step, the conveying speed is reduced by the predetermined moving speed. The conveyance speed is set to be smaller by the predetermined moving speed when the predetermined magnification is set to a large value and the predetermined magnification is 100% or less.

According to a fifteenth aspect of the present invention, in the image forming method of the twelfth aspect, the predetermined moving speed is set at the predetermined magnification in the moving direction setting step. It is characterized by the following.

According to a sixteenth aspect of the present invention, in the image forming method according to the fifteenth aspect, when the predetermined magnification exceeds 100% in the moving direction setting step, the document is conveyed in the predetermined moving direction. Direction, and when the predetermined magnification is 100% or less, the predetermined moving direction is set to a direction opposite to a direction in which the document is transported.

According to a seventeenth aspect of the present invention, in the image forming method of the twelfth aspect, the predetermined moving speed is set by the number of the originals in the moving direction setting step.

An image forming method according to an eighteenth aspect of the present invention is the image forming method according to the seventeenth aspect, wherein the predetermined moving direction is changed each time the document is read in the moving direction setting step.

In the image forming method according to the nineteenth aspect, in the image forming method according to the eighteenth aspect, when the original is an odd numbered sheet in the moving direction setting step, the predetermined moving direction is changed to the conveying direction of the original. And when the document is not an odd-numbered document, the predetermined moving direction is set in a direction opposite to a direction in which the document is transported.

According to a twentieth aspect of the present invention, in the image forming method according to any one of the seventeenth to nineteenth aspects, the transport speed is set based on the number of the documents in the transport speed setting step. Features.

According to a twenty-first aspect of the present invention, in the image forming method according to the twentieth aspect, when the original is an odd numbered sheet in the conveying speed setting step, the conveying speed is increased by the predetermined moving speed. When the document is not an odd numbered sheet, the transport speed is set to be lower by the predetermined moving speed.

According to a twenty-second aspect of the present invention, in the image forming method according to any one of the twelfth to twenty-first aspects, the predetermined moving speed is lower than the transport speed.

[0027]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) The configuration of an image forming apparatus according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a sectional view illustrating a schematic configuration of the image forming apparatus according to the first embodiment.

In FIG. 1, an image forming apparatus 1 includes an automatic document feeder (ADF) 2 and a document table glass (contact glass) 3 at its upper part. ADF2 uses the AD
The originals set in F2 are sequentially conveyed to a predetermined position on the original glass 3 in a sheet-through manner. Platen glass 3
A document illumination lamp 4 using a halogen lamp or the like, scanning mirrors 5, 6, 7 for changing the trajectory of reflected light obtained by exposing the document with the document illumination lamp 4, and digital data An optical scanning unit constituted by a CCD unit 8 for converting the image data into an image is provided.

The optical scanning unit can be freely moved in the normal direction and the horizontal direction of the original paper by motors (not shown), and is moved in each direction to expose the original conveyed on the original glass 3. Perform a scan. The reflected light obtained by the exposure scanning is sent to the CCD unit 8 via the scanning mirrors 5, 6, 7. The CCD unit 8 mainly includes an imaging device 9 using a known CCD or the like, an imaging lens 10 that forms a reflected light image on the imaging device 9, and a C drive that drives the imaging device 9.
An image signal (analog data) of a document formed on the image sensor 9 is converted into digital data (for example, 8-bit digital data or the like) and output to the controller 12. The controller unit 12
It is connected to the CCD unit 8, the operation panel 13, and the laser unit 17, controls each part in the image forming apparatus 1, and outputs from the CCD unit 8 based on a manual operation from the operation panel 13 by a user (user). Image processing of the obtained digital data.

In addition to the above, the image forming apparatus 1 includes a photosensitive drum 14 which is a cylindrical or columnar latent image carrier, and a pre-exposure device which removes electricity from the outer peripheral surface of the photosensitive drum 14 to prepare for the next image formation. A photosensitive drum which is constituted by a lamp 15, a primary charger 16 for charging the outer peripheral surface of the photosensitive drum 14 to a predetermined potential distribution to form a latent image, and a known semiconductor laser or the like, and which has been subjected to a charging process of the primary charger 16 A laser unit 17 that exposes the outer peripheral surface of the photosensitive drum 14 based on digital data input from the controller unit 12 and forms an electrostatic latent image on the outer peripheral surface of the photosensitive drum 14 according to given image data; The electrostatic latent image formed on the outer peripheral surface of the toner image is developed (toner image) by applying a developer (hereinafter referred to as “toner”).
And a developing unit 18 for developing the toner.

Around the photosensitive drum 14, in addition to the pre-exposure lamp 15, the primary charger 16, and the developing device 18,
A pre-transfer charger 19 for applying a high voltage to the visible image on the outer peripheral surface of the photosensitive drum 14 before the transfer, a transfer charger 20 for transferring the toner image to the recording paper P by corona discharge or the like, and the transfer process is completed. A separation charger 21 for separating the recording paper P from the outer peripheral surface of the photosensitive drum 14 and a cleaner 22 for removing and recovering the developer remaining on the outer peripheral surface of the photosensitive drum 14 after the end of the transfer are arranged.

Further, the image forming apparatus includes a fixing device 27 for performing a fixing process by supplying heat and applying pressure, a conveyance belt 28 for conveying the recording paper P on which the toner image has been transferred in the transfer area to the fixing device 27, Flapper 29, intermediate tray 30,
And a staple sorter 31. The staple sorter 31 is a bookbinding device (glue binder) depending on the application.
It can be changed to 32.

The toner image formed on the outer peripheral surface of the photosensitive drum 14 is applied with a high voltage by a pre-transfer charger 19. The recording paper P to be transferred is transferred to the photosensitive drum 14 at a timing set by the registration roller 26 from one of the paper feeding units 23, 24, and 25 that can store a plurality of recording papers P classified by size. The sheet is conveyed to a transfer area between the charging device 20. The recording paper P that has reached the transfer area has its toner image transferred onto the outer peripheral surface of the photosensitive drum 14 by corona discharge or the like of the transfer charger 20, and is then separated from the outer peripheral surface of the photosensitive drum 14 by the separation charger 21. . On the other hand, the developer remaining on the outer peripheral surface of the photosensitive drum 14 after the transfer process is removed by the cleaner 22 for the next image formation.

The flapper 29 conveys the recording paper P subjected to the fixing process by the fixing device 27 to the intermediate tray 30 or the staple sorter 31 based on the instruction from the control section 12.
The glue binder 3 is used instead of the staple sorter 31.
2 is provided, the sheet is conveyed to the glue binder 32. When the mode (multiple transfer mode) for forming a plurality of images on the same surface is set for the intermediate tray 30,
The recording paper P conveyed via the conveying rollers 33, 34, 35, 36 is conveyed to the re-conveying roller 37 without turning over. On the other hand, when the mode for forming an image on both sides of the recording paper P (double-sided copy mode) is set, the recording paper P is reversed and transported to the re-transport roller 37.

The re-conveying roller 37 is for conveying the recording paper P conveyed from the intermediate tray 30 to the registration roller 26. The recording paper P reaching the registration roller 26 is conveyed again to the transfer area. The sheet is conveyed to a fixing device 27 by a conveying belt 28 and subjected to a fixing process, and then discharged from a staple sorter 31 or a glue binder 32. When a mode (continuous copy mode) for continuously forming images on a plurality of recording papers P is set, the staple sorter 31 separates a plurality of recording papers P that have been subjected to a fixing process within a predetermined number of papers. The sheets are sorted and stapled one by one for each bin 31A. When the image forming apparatus 1 includes the staple sorter 31, the staple unit 31B staples the recording paper P under the control of the controller unit 12. On the other hand, the glue binder 32 is a device for binding a plurality of recording papers P on which the fixing process has been performed. When the glue binder 32 is provided in the image forming apparatus 1, the binder unit 32A is controlled by the control unit 12. Based on the information, a spine is glued to a bundle of a plurality of sheets of recording paper P that have been subjected to a fixing process, and bookbinding is performed.

The white plate 62 is for eliminating the influence of the light distribution in the longitudinal direction of the original illumination lamp 4 and the sensitivity unevenness of the image pickup device 9 and the like, and the surface exposed by the original illumination lamp 4 is coated with white paint. Have been. Image data obtained when the white painted surface is exposed and scanned by the optical unit is output to the controller unit 12 via the CCD unit 8.

The controller section 12 shown in FIG. 1 has the configuration shown in FIG. FIG. 2 is a block diagram showing a schematic configuration of the controller unit 12 of FIG.

In FIG. 2, a controller section 12 controls a CPU 38 for controlling each section in the image forming apparatus 1 and an RO that stores in advance a control procedure (control program) and the like.
M39, a RAM 40 of a main storage device used as a work storage area for temporarily storing image data, an I / O port 41 of an interface for each unit, and a CCD unit 8 based on a manual operation of the operation panel 13 by a user. An image processing unit 42 for performing image processing of the output digital data; a bus driver / address decoder circuit 43 for controlling the flow of data between the CPU 38 and each unit
And

The CPU 38 includes a bus driver / address decoder 43 connected to an address bus and a data bus.
ROM39, RAM40, I / O port 41,
And an image processing unit 42, and further, an I / O port 4
1, an operation panel 13, a motor 44 for driving the optical scanning unit, an electromagnetic clutch 45, an electromagnetic solenoid 46, and a paper detection sensor 47 for detecting the recording paper P conveyed to the transfer area. And a high-voltage unit 5 for outputting a high voltage to the primary charger 16 and the like, and a toner remaining amount detection sensor 48 for detecting the amount of toner stored in the developing device 18.
1, provided in a non-image area on the outer peripheral surface of the photosensitive drum 14 and connected to a beam detection sensor 52 for receiving the laser La emitted from the laser unit 17.

The image data output from the CCD unit 8 is subjected to predetermined image processing in the image processing unit 42 and is output to the laser unit 17 connected to the image processing unit 42. The laser unit 17 forms an image by irradiating the photosensitive drum 14 with a laser La based on the image data,
The beam detection sensor 52 monitors the irradiation state of the laser La.

The image processing section 42 shown in FIG. 2 has the configuration shown in FIG. FIG. 3 is a block diagram illustrating a schematic configuration of the image processing unit 42.

In FIG. 3, the image processing section 42 includes a shading circuit 53, a scaling circuit 54 connected to the shading circuit 53, an edge emphasizing circuit 55 connected to the scaling circuit 54, and an edge emphasizing circuit 55. The connected γ conversion circuit 56, the binarization circuit 57 connected to the γ conversion circuit 56, and the combination connected to the binarization circuit 57 and further connected to the image memory 59 via the memory control unit 61. Circuit 5
8 and a PWM circuit 60 connected to the synthesizing circuit 58.

The shading circuit 53 corrects the variation between the pixels of the image data output from the CCD unit 8 using shading correction data, which will be described later, and outputs the corrected data to the scaling circuit 54. When this occurs, an error signal is output to the I / O port 41. When the reduction copy mode is set, the scaling circuit 54 thins out image data,
When the enlargement copy mode is set, the image data is interpolated and the processed image data is temporarily stored. The edge enhancement circuit 55 converts the image data into 5
In addition to performing secondary differentiation in a × 5 window, edge enhancement processing of image data is performed and output to the γ conversion circuit 56. The γ conversion circuit 56 converts the image data, which is luminance data, into density data in order to output the image data to the laser unit 17.
In this case, the image data is changed to a gradation expression using an intermediate density or the like in accordance with a mode for forming an image on the recording paper P, so that the image data is converted into density data by table search.

The image data output from the γ conversion circuit 56 is still multi-valued data only after being converted from luminance data to density data, and needs to be converted into binary data. The binarization circuit 57 converts digital data from multi-level data to binary data by a known ED method or the like, and outputs the converted data to the synthesis circuit 58. The memory control unit 61 is a DRAM
The read / write control is performed on the image memory 59 using (Dynamic RAM) or the like. In the synthesizing circuit 58, the image data stored in the image memory 59 and the synthesizing circuit 58
Based on a predetermined request, either one of the data is selected or the two data are combined and output to a data conversion circuit (PMW circuit) 60. P
The MW circuit 60 converts the digital data into a pulse signal corresponding to a mode for forming an image based on a manual operation of the operation panel 13 by a user, and outputs the pulse signal to the laser unit 17.

The operation panel 13 shown in FIG. 2 has the configuration shown in FIG. FIG. 4 is an overhead view showing an external configuration of the operation panel 13 of FIG.

In FIG. 4, the operation panel 13 takes the form of a known touch panel, and has a display 63 serving as display means.
, Ten keys 64, a start key 65, a reset key 66, a stop key 67, a clear key 68, #
Key 69, ID key 70, remaining heat key 71, interrupt key 72, power indicator lamp 73, power switch 7
4 is provided. The user manually operates the operation panel 13 to set various modes for forming an image such as a copy, the number of copies, an image density at the time of copying, and the like. Part 12
Sent to

The display 63 displays messages such as instructions and warnings to the user, and the numeric keypad 64 is a key for the user to input the number of copies and the like. A copy (start) key 65 is a key for instructing a copy start, and a reset key 66 is a key for returning settings such as an operation mode to initial settings. Stop key 6
Reference numeral 7 denotes a key for interrupting the operation, and a clear key 68 is a key for returning the number of copies and the like input by the ten keys 64 to an initial set value. The # key 69 is a key for using an attached option, and the ID key 7
0 is a key for performing authentication for enabling an operation only for a specific user. The remaining heat key 71 is a key for turning on / off the remaining heat mode, and an interrupt key 7
Reference numeral 2 denotes a key for performing a copy operation set separately during the copy operation.
The N / OFF state is notified by turning on / off the lamp. The power switch 74 is a key for turning on / off the power. When the power is off, a DC power supply (not shown)
The secondary circuit connected to the C power supply is in a conductive (ON) state, and the display unit 61 and the primary circuit (not shown) connected to the DC power supply are in a non-conductive (OFF) state.
At the time of N, all of the DC power supply, the primary side circuit, the secondary side circuit, and the display unit 61 are turned on.

Next, the ADF in the image forming apparatus shown in FIG.
The reading operation of a document sheet-through at a predetermined position on the platen glass 3 (hereinafter referred to as "sheet-through reading") will be described with reference to FIGS. 5, 6, and 7. FIG. FIG. 5 is a state diagram showing a document standby state during sheet-through reading in the image forming apparatus of FIG.
3 is a state diagram showing a document reading state at the time of sheet through reading in the image forming apparatus of FIG.

In FIG. 5, an original transport belt B provided on the ADF 2 is an original transport belt for transporting the original D to a predetermined position on the original platen glass 3. The optical scanning unit including the original illumination lamp 4, the scanning mirrors 5, 6, and 7 has moved to the sheet-through reading position below the original platen glass 3, and the original D is located just before the reading position on the original platen glass 3 (the original). (Standby position). At this time, if the document illumination lamp 4 exposes the document table glass 3, there is no document at the reading position, so that the image on the document conveying belt B is read. The reflected light exposed by the document illumination lamp 4 is transmitted to the CCD unit 8 via the scanning mirrors 5, 6, and 7.
Sent to

In FIG. 6, the original conveying belt B is the original D
, The document D is sequentially conveyed at a constant speed toward the left side (arrow) in the figure. When the document D is conveyed to the reading position of the optical scanning unit, the document illumination lamp 4 exposes the document D, and the reflected light is sent to the CCD unit 8 as image data.

FIG. 7 is a timing chart showing the operation of the document conveying belt B at the time of sheet through reading in the image forming apparatus of FIG. In the timing chart, the horizontal axis represents the document transport time T, and the vertical axis represents the transport of the document transport belt B /.
This represents a stop operation, and shows an operation when three originals are read. In FIG. 7, in the section indicated by the arrows of,,, the document conveying belt B is conveying the document D and reading the image of the document D. In the section before the start of,, The document transport belt B stops transporting the document D and is in a standby state for reading the document D. As described above, the document transport belt B repeatedly transports / stops the document D, and a plurality of documents are sequentially read.

Next, at the time of sheet-through reading of the image forming apparatus of FIG. 1, the image data read when no dust or the like has adhered to the document table glass 3 and the dust or the like has adhered to the document table glass 3. The difference from the image data read at the time of reading will be described with reference to FIG. FIG. 8 is a graph showing the luminance of one line of CCD pixels of image data read at the time of sheet-through reading in the image forming apparatus of FIG. 1, and (a) shows dust on the platen glass 3. 3B shows a case where dust or the like has adhered to the document table glass 3. The vertical axis of the graph indicates the luminance. If the read object is a bright white type, it indicates high luminance close to FFH, and if it is a dark black type, 00H.
Shows a low luminance. In both FIGS. 8A and 8B, the luminance at both ends of the data is reduced due to the low light intensity of the original illumination lamp 4.

As shown in FIG. 8A, the platen glass 3
If no dust or the like adheres to the document, the CCD unit 8 reads the document conveying belt B, and the data output from the CCD unit 8 shows a value close to FFH.
On the other hand, as shown in FIG. 8B, when dust or the like adheres to the document table glass 3, the light of the document illumination lamp 4 is blocked, and the amount of light irradiating the document conveying belt B is reduced. The data output from 8 indicates 30H close to 00H. As described above, when the luminance is extremely reduced due to the influence of the attached matter such as dust, the image may not be correctly read.

FIGS. 9 and 10 are flowcharts showing sheet-through reading control processing of the image forming apparatus according to the first embodiment. This process is called at regular intervals or as needed from the main control process (sequence).

In FIG. 9, when the copy key 65 of the operation panel 13 is pressed (YE in step S1001)
S), black shading for uniformly correcting the variation of each pixel of the image data output from the CCD unit 8 when the document illumination lamp 4 is turned off (step S100)
2) Turn on the document illumination lamp 4 (step S100)
3). When the original illumination lamp 4 reaches a required light amount, C
The white shading for uniformly correcting the variation between the pixels of the image data output from the CD unit 8 is performed (step S1004), and the optical scanning unit is moved to the sheet-through reading position (step S1005). In addition,
In this embodiment, the center of the platen glass 3 is the sheet-through reading position, but may be another position. next,
The first document set on the ADF 2 is transported toward the document standby position by the document transport belt B (step S1).
006). In this embodiment, the document is conveyed after the optical scanning unit is moved to the sheet-through reading position. However, the document may be conveyed simultaneously with the processing in steps S1002 to S1005. .

In FIG. 10, when the conveyance of the original to the original standby position is completed (YES in step S1007), the enlargement / reduction magnification of the original set on the operation panel 13 becomes 10
It is determined whether it is 0% or less (step S100).
8). As a result of this determination, the enlargement / reduction magnification of the document is 10
If it is 0% or less, the document transport speed at the time of sheet through by the ADF 2 is set smaller than the document transport speed determined by the magnification by the moving speed (α) of the optical scanning unit (step S1009), and the process proceeds to step S1010.

The moving speed of the optical scanning unit is set to 5 times when reading an A4 original in order to reduce the influence of the original reading state due to the difference in the sheet through reading position.
It is set so that the movement amount is about mm. In the present embodiment, the document conveyance speed is set to a magnification of 100%.
In the case of%, the moving speed of the optical scanning unit is set to about 6 mm / sec because it is 260 mm / sec. In this case, for example, 0.04
When dust having a size of about 2 mm is read at a magnification of 100%, an image is formed with a size of about 1.8 mm.

In step S1010, the document at the document standby position is conveyed by the document conveying belt B to the document reading start position of the optical scanning unit. When the document is conveyed to the document reading start position (YE in step S1011)
S), reading of the document by the optical scanning unit is started, and at the same time, the optical scanning unit starts moving in the direction opposite to the document transport direction (rightward in FIG. 6) at the document transport speed set in step S1009 (step S1012). Then, the process proceeds to step S1013.

When the image reading of the original is completed (YES in step S1013), the movement of the optical scanning unit is stopped, and it is determined whether or not the next original exists (step S1).
014), if the result of this determination is that there is a next original,
The optical scanning unit is moved to the sheet-through reading position (step S1015), and the ADF 2 starts transporting the next document toward the document standby position (step S101).
6), and return to step S1007.

On the other hand, as a result of the determination in step S1008,
The enlargement / reduction magnification set on the operation panel 13 is 100
When the value exceeds%, the document conveying speed determined by the magnification is set to be higher by the moving speed (α) of the optical scanning unit (step S1017).

Next, the document at the document standby position is transported by the document transport belt B to the document reading start position of the optical scanning unit (step S1018). When the document is conveyed to the document reading start position (YES in step S1019), reading of the document by the optical scanning unit is started, and at the same time, the optical scanning unit sets the document conveyance speed set in step S1017 in the same direction as the document conveyance direction ( FIG.
(To the left of FIG. 5) (step S1020), the process proceeds to step S1013, and the subsequent processing is performed.

As a result of the determination in step S1014,
When there is no next original, the original is discharged (step S1).
021), the optical scanning unit is returned to the normal standby position (step S1022), and the process ends.

In the conventional image forming apparatus, the image reading is performed while the optical scanning unit is stopped. Therefore, the conveying speed of the original is determined by the enlargement / reduction magnification, and when the magnification is set in a wide range, the sheet-through conveyance speed of the ADF 2 is changed. Had to be designed extensively. In the present embodiment, since the image is read while the optical scanning unit is moving, the magnification of the enlargement / reduction is determined by the document conveying speed and the relative speed between the optical scanning unit. Since the optical scanning unit is moved in the same direction in the opposite direction when it is smaller than 100%, it is possible to enlarge / reduce the image formation without changing the range of the sheet-through conveyance speed of the ADF 2 compared to the related art. .

According to the first embodiment, after the optical scanning unit is moved to the sheet-through reading position (step S1005), when the enlargement / reduction magnification of the document is 100% or less (YES in step S1008). The optical scanning unit is moved in the direction opposite to the original transport direction at a set original transport speed smaller than the original transport speed determined by the magnification by the moving speed of the optical scanning unit to read the image of the original and to enlarge or reduce the original. When the magnification exceeds 100% (NO in step S1008), the optical scanning unit is moved in the same direction as the original conveying direction at the original conveying speed set to be higher than the original conveying speed determined by the magnification by the moving speed of the optical scanning unit. The original image is read by the original. Even when the optical scanning unit is attached, the optical scanning unit moves from a predetermined position, so that the influence of dust or the like on image formation can be reduced. Further, since the magnification is set based on the relative speed between the optical scanning unit and the document, A
This can be realized without changing the document transport capacity of the DF2.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
An image forming apparatus according to the present embodiment will be described with reference to FIGS. In the second embodiment,
The configuration is the same as that of the above-described first embodiment, and only the differences in the operation and the like from the above-described first embodiment will be described. FIGS. 11 and 12 are flowcharts showing sheet-through reading control processing of the image forming apparatus according to the second embodiment. This processing is also performed from the main control processing (sequence) similarly to FIGS. 9 and 10. It is called at regular intervals or as needed.

In FIG. 11, when the copy key 65 of the operation panel 13 is depressed (YES in step S2001), as in the first embodiment, the black for uniformly correcting the variation of each pixel of the image data is obtained. Shading is performed (step S2002), the original illumination lamp 4 is turned on (step S2003), and when the original illumination lamp 4 reaches a required light amount, white shading for uniformly correcting the variation of each pixel of the image data is performed (step S2004). The optical scanning unit is moved to the sheet-through reading position (Step S2005). In the present embodiment, the center of the platen glass 3 is set as the sheet-through reading position, but may be another position. Next, the information of the number of documents is set to 1 (step S2006), and the first document set on the ADF 2 is transported toward the document standby position by the document transport belt B (step S2007). In this embodiment, after the optical scanning unit is moved to the sheet-through reading position, the document is conveyed. However, the document may be conveyed simultaneously with the processing in steps S2002 to S2005. .

In FIG. 12, when the transport of the original to the original standby position is completed (YES in step S2008), it is determined whether or not the transported original is an odd-numbered original based on information on the number of originals (FIG. 12). Step S2009). As a result of this determination, when the original is an odd-numbered original, the ADF
2 The document transport speed during sheet through by
The document conveying speed determined by the reduction ratio is set to be higher by the moving speed (α) of the optical scanning unit (step S).
2010), the document at the document standby position is transported by the document transport belt B to the document reading position of the optical scanning unit (step S2011).

When the original is conveyed to the original reading start position (movement start position of the optical scanning unit) (step S2).
012), the reading of the document is started by the optical scanning unit, and at the same time, the optical scanning unit
At the document conveyance speed set at 010, movement in the same direction as the document conveyance direction (left direction in FIG. 6) is started (step S20).
13).

When the image reading of the original is completed (YES in step S2014), the movement of the optical scanning unit is stopped, and it is determined whether or not the next original exists (step S2).
015) As a result of this determination, when there is a next original,
One is added to the information on the number of documents (step S201).
6) The conveyance of the next document is started by the ADF 2 toward the document standby position (step S2017), and the process proceeds to step S2.
Return to 008.

On the other hand, as a result of the determination in step S2009,
If the original to be read is not an odd-numbered original, the original transport speed at the time of sheet-through by the ADF 2 is set to be smaller than the original transport speed determined by the enlargement / reduction magnification of the original by the moving speed of the optical scanning unit (α) (step S2
018).

Next, the document at the document standby position is started to be transported to the document reading position of the optical scanning unit by the document transport belt B (step S2019), and the document started to be transported by the document transport belt B is moved to the document reading start position. It is determined whether or not the sheet has been conveyed to (the movement start position of the optical scanning unit) (step S2020). At this time, the original reading start position (movement start position of the optical scanning unit)
Is farther than the normal sheet-through reading position, the reading is determined to be slower by that distance. When the document is conveyed to the document reading start position (step S20)
20), the reading of the document is started by the optical scanning unit, and at the same time, the optical scanning unit
At step S202, the document is moved in the direction opposite to the document transport direction (rightward in FIG. 6) at the document transport speed set in step S18.
1), perform the processing of step S2014 and subsequent steps.

As a result of the determination in step S2015,
When there is no next original, the original is discharged (step S2).
022), the optical scanning unit is returned to the normal standby position (step S1023), and this processing ends.

As a result, the optical scanning unit is not returned to the sheet-through reading position each time an image of one document is read, so that the reading time for a plurality of documents can be reduced, and the image of the optical scanning unit can be further reduced. The moving range at the time of reading can be designed to be small.

According to the second embodiment, after the optical scanning unit is moved to the sheet-through reading position (step S2).
005), when the document is an odd numbered sheet (step S20)
09, YES), the optical scanning unit is moved in the same direction as the original transport direction at the original transport speed set by the moving speed of the optical scanning unit higher than the original transport speed determined by the magnification, and the image of the original is read. If the original is not an odd number (NO in step S2009), the original is moved by moving the optical scanning unit in the same direction as the original transport direction at the original transport speed set to be smaller than the original transport speed determined by the magnification by the moving speed of the optical scanning unit. The original platen glass 3 exposed by the original illumination lamp 4
The optical scanning unit moves from the fixed position even when dust or the like is attached to the fixed position of the, so that the influence of dust or the like on image formation can be reduced, and the optical scanning unit is returned to the sheet-through reading position. By reading the next document without reading, a plurality of documents can be read in a short time without changing the document transport capability of the ADF 2.

[0076]

As described above in detail, according to the image forming apparatus according to the first aspect and the image forming method according to the twelfth aspect, the image information reading means is provided when the original is transported on the original table. Since the image information of the original conveyed at the conveying speed is read while moving from the predetermined position in the predetermined moving direction at the predetermined moving speed, dust or the like adheres to the predetermined position of the original table exposed by the illumination lamp. Even in such a case, the influence of dust and the like on image formation can be reduced by moving the image reading unit from the predetermined position.

An image forming apparatus according to claim 2 and claim 1
According to the image forming method described in Item 3, since the transport speed is set based on the predetermined magnification, it is possible to easily enlarge / reduce the image formation without changing the document transport capability of the document transport device.

An image forming apparatus according to claim 3 and claim 1
According to the image forming method of (4), when the predetermined magnification exceeds 100%, the conveying speed is set to be higher by the predetermined moving speed,
When the predetermined magnification is equal to or less than 100%, the conveying speed is set to be lower by the predetermined moving speed, so that the enlargement / reduction of image formation can be more easily performed without changing the original conveying ability of the original conveying device. .

The image forming apparatus according to the fourth aspect and the first aspect.
According to the image forming method of the fifth aspect, the moving direction setting means sets the predetermined moving speed based on the predetermined magnification, so that the enlargement / reduction of image formation can be performed without changing the document conveying capability of the document conveying device. Can be performed accurately.

An image forming apparatus according to claim 5, and claim 1.
According to the image forming method described in Item 6, the predetermined magnification is 100%
When the predetermined magnification is less than 100%, the predetermined moving direction is set to be opposite to the original conveying direction when the predetermined magnification is 100% or less.
Enlargement / reduction of image formation can be performed more accurately without changing the document carrying capacity of the document carrying device.

An image forming apparatus according to claim 6 and claim 1
According to the image forming method described in Item 7, since the predetermined moving speed is set based on the number of documents, it is possible to perform optimal image reading according to a plurality of documents.

An image forming apparatus according to claim 7 and claim 1
According to the image forming method described in Item 8, since the predetermined moving direction is changed each time a document is read, it is possible to perform optimal image reading according to a plurality of documents and reduce the reading time.

An image forming apparatus according to claim 8 and claim 1
According to the image forming method described in Item 9, when the document is an odd-numbered document, the predetermined moving direction is set to the same direction as the document conveyance direction, and when the document is not an odd-numbered document, the predetermined moving direction is Since the setting is made in the direction opposite to the transport direction, optimal image reading corresponding to a plurality of documents can be performed, and enlargement / reduction of image formation can be easily performed without changing the document transport capability of the document transport device. .

An image forming apparatus according to claim 9 and claim 2
According to the image forming method described in No. 0, the transport speed is set based on the number of documents, so that optimal image reading is performed without changing the document transport capability of the document transport device,
Enlargement / reduction of image formation can be easily performed.

According to the image forming apparatus of the tenth aspect and the image forming method of the twenty-first aspect, when an original is an odd numbered sheet, the conveying speed is set to be higher by a predetermined moving speed, and the number of the originals is odd. If not, the transport speed is set to be lower by the predetermined moving speed, so that optimal image reading corresponding to a plurality of documents is performed, and enlargement / reduction of image formation can be performed without changing the document transport capability of the document transport device. More easily.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to a first embodiment.

FIG. 2 is a block diagram showing a schematic configuration of a controller unit 12 in FIG.

FIG. 3 is a block diagram illustrating a schematic configuration of an image processing unit shown in FIG. 2;

FIG. 4 is an overhead view showing the appearance of the operation panel 13 of FIG.

FIG. 5 is a state diagram illustrating a document standby state during sheet-through reading in the image forming apparatus of FIG. 1;

FIG. 6 is a state diagram showing a document reading state at the time of sheet through reading in the image forming apparatus of FIG. 1;

FIG. 7 is a timing chart showing an operation of a document conveying belt B at the time of sheet-through reading in the image forming apparatus of FIG.

8 is a graph showing the luminance of one line of CCD pixels of image data read at the time of sheet-through reading in the image forming apparatus of FIG. 1; FIG. 8A shows a case where the platen glass 3 is normal; (B) shows a case where dust or the like has adhered to the platen glass 3.

FIG. 9 is a flowchart illustrating sheet-through reading control processing of the image forming apparatus according to the first embodiment.

FIG. 10 is a flowchart illustrating sheet-through reading control processing of the image forming apparatus according to the first embodiment.

FIG. 11 is a flowchart illustrating sheet-through reading control processing of the image forming apparatus according to the second embodiment.

FIG. 12 is a flowchart illustrating sheet-through reading control processing of the image forming apparatus according to the second embodiment.

[Explanation of symbols]

 Reference Signs List 1 image forming apparatus 2 automatic document feeder (ADF) 3 platen glass (contact glass) 4 document illumination lamp 5, 6, 7 scanning mirror 8 CCD unit 12 controller section 38 CPU 42 image processing section 53 shading circuit 54 scaling circuit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H076 AA58 BA03 BA04 BA14 BA20 BA22 BA33 BA45 BA64 BA68 BA95 BB04 BB05 3F049 AA10 EA10 EA12 EA22 LA01 LB02 5B047 AA01 BA01 CA08 CB10 5C072 AA01 BA13 DA05 EA05 MB02 NA05

Claims (22)

[Claims] A document feeder for feeding a document onto a document table; and image information reading means arranged at a predetermined position to read image information of the document conveyed by the document feeder, In an image forming apparatus which forms an image by enlarging / reducing the image information read by the image information reading means at a predetermined magnification, the image information reading means is moved from the predetermined position at a predetermined moving speed in a predetermined moving direction. Moving means for moving; conveying speed setting means for setting a conveying speed of the document by the document conveying means; moving direction setting means for setting the predetermined moving direction of the image information reading means by the moving means; While moving the image information reading means in the predetermined moving direction at the predetermined moving speed, the image information of the original conveyed at the conveying speed is read. An image forming apparatus comprising: a control unit configured to control the image forming apparatus to take the image. 2. The image forming apparatus according to claim 1, wherein the transport speed setting unit sets the transport speed based on the predetermined magnification. 3. The transfer speed setting means sets the transfer speed higher by the predetermined moving speed when the predetermined magnification exceeds 100%, and sets the transfer speed when the predetermined magnification is 100% or less. 3. The image forming apparatus according to claim 2, wherein the speed is set lower by the predetermined moving speed. 4. The image forming apparatus according to claim 1, wherein the moving direction setting unit sets the predetermined moving speed based on the predetermined magnification. 5. The moving direction setting means, when the predetermined magnification exceeds 100%, sets the predetermined moving direction to the same direction as the document conveying direction, and sets the predetermined magnification to 1%.
5. The method according to claim 4, wherein the predetermined moving direction is set to a direction opposite to a direction in which the original is conveyed when the ratio is not more than 00%.
The image forming apparatus as described in the above. 6. The image forming apparatus according to claim 1, wherein the moving direction setting unit sets the predetermined moving speed based on the number of the documents. 7. The image forming apparatus according to claim 6, wherein the moving direction setting unit changes the predetermined moving direction each time the document is read. 8. The moving direction setting means sets the predetermined moving direction to the same direction as the conveying direction of the document when the document is an odd-numbered sheet, and sets the predetermined moving direction to the same direction when the document is not an odd-numbered sheet. 8. The image forming apparatus according to claim 7, wherein a predetermined moving direction is set in a direction opposite to a direction in which the document is transported. 9. The image forming apparatus according to claim 6, wherein the transport speed setting unit sets the transport speed based on the number of the documents. 10. The transport speed setting means sets the transport speed higher by the predetermined moving speed when the document is an odd numbered sheet, and sets the transport speed to the predetermined number when the document is not an odd numbered sheet. The image forming apparatus according to claim 9, wherein the image forming apparatus is set smaller by a predetermined moving speed. 11. The image forming apparatus according to claim 1, wherein the predetermined moving speed is lower than the transport speed. 12. An image information reading means arranged at a predetermined position to read image information of a document conveyed on a document table, wherein said image information read by said image information reading means is converted at a predetermined magnification. In an image forming method of an image forming apparatus for forming an image by enlarging / reducing, a moving step of moving the image information reading means from the predetermined position at a predetermined moving speed in a predetermined moving direction; A conveying speed setting step to set; a moving direction setting step to set the predetermined moving direction of the image information reading means; and moving the image information reading means in the set predetermined moving direction at the predetermined moving speed. A control step of reading the image information of the document conveyed at the conveyance speed while reading the document. 13. The image forming method according to claim 12, wherein, in the transport speed setting step, the transport speed is set based on the predetermined magnification. 14. In the transport speed setting step, when the predetermined magnification exceeds 100%, the transport speed is set higher by the predetermined moving speed, and the predetermined magnification becomes 1
14. The image forming method according to claim 13, wherein the conveying speed is set to be smaller by the predetermined moving speed when the speed is equal to or less than 00%. 15. The image forming method according to claim 12, wherein in the moving direction setting step, the predetermined moving speed is set based on the predetermined magnification. 16. In the moving direction setting step, when the predetermined magnification exceeds 100%, the predetermined moving direction is set to the same direction as the document conveyance direction, and the predetermined magnification is 100% or less. 16. The image forming method according to claim 15, wherein the predetermined moving direction is set to a direction opposite to a direction in which the document is transported. 17. The image forming method according to claim 12, wherein in the moving direction setting step, the predetermined moving speed is set based on the number of the documents. 18. The image forming method according to claim 17, wherein in the moving direction setting step, the predetermined moving direction is changed every time the document is read. 19. The moving direction setting step, wherein when the document is an odd numbered sheet, the predetermined moving direction is set to the same direction as the document conveying direction, and when the document is not an odd numbered sheet, 19. The image forming method according to claim 18, wherein a predetermined moving direction is set in a direction opposite to a direction in which the document is transported. 20. The image forming method according to claim 17, wherein in the transport speed setting step, the transport speed is set based on the number of the originals. 21. In the transport speed setting step, when the document is an odd-numbered document, the transport speed is set higher by the predetermined moving speed, and when the document is not an odd-numbered document, the transport speed is increased. 21. The image forming method according to claim 20, wherein the setting is made smaller by a predetermined moving speed. 22. The image forming method according to claim 12, wherein the predetermined moving speed is lower than the transport speed.