JP2017028604A - Image reading device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve image quality of a seam of an image sensor regardless of types of scripts.SOLUTION: An image reading device 4, which is configured so as to read images while moving a script on a plurality of CISs arranged zigzag using conveying rollers 107 and 108 and has image synthesizing means that delays front-side image data and synthesizes the data with rear-side image data in a line, comprises: a CIS unit driving mechanism 503 that moves arrangements of CIS 101-105 so that the arrangements are switched into either synchronous arrangements or short-distance arrangements; and a RAM 714 memorizing delay time t1 an t2 of the front-side image data corresponding to the synchronous arrangements and the short-distance arrangements respectively. An image synthesizing processing portion 704 is configured to synthesize the front-side image data and the rear-side image data in a sub-scanning direction on the basis of the arrangements of CIS 101-105 based on an instruction by a CPU 711 and the delay time t1 and t2 of the front-side image data according to the synchronous arrangements and the short-distance arrangements respectively.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image reading apparatus used in a printer or the like and an image forming apparatus using the same, and more particularly to adjustment of joint positions of images by image sensors arranged in a staggered manner.

  In order to realize reading by a wide CIS such as A0 size, there is a zigzag method in which A3 and A4 size CIS as shown in FIGS. 10 and 11 are arranged in a zigzag manner and realized at low cost. One such as A0 size CIS is expensive because there is little demand, but A3 and A4 size CIS are versatile and mass-produced and are low cost, so they are used in the staggered method .

  In the staggered method, each CIS needs to be read in the main scanning direction or the sub-scanning direction as if it were read with a single CIS. Image connection adjustment in the main scanning direction is performed by adjusting the reading range of the CIS, and image connection adjustment in the sub-scanning direction is performed by adjusting the delay time of the delay memory.

  In the CIS splicing method reading, there is a problem that the image at the joint portion is shifted in the sub-scanning direction due to the deviation of the image synthesis timing in the sub-scanning direction due to the occurrence of unevenness of the document conveyance speed. FIG. 12 shows an example of the sub-scan joint misalignment image. As shown in FIG. 12, when the original image is read, the image is shifted in the sub-scanning direction at the CIS connecting position. Due to the occurrence of uneven document conveyance speed from the leading edge to the trailing edge, the amount of shift of the joint varies depending on each position in the sub-scanning direction.

  In order to solve such a problem, Patent Document 1 discloses a configuration in which the arrangement interval of the front and rear CISs is an integral multiple of the circumferential length of the conveying roller. With this configuration, it is possible to reduce the occurrence of uneven conveyance speed due to the eccentricity and twisting of the conveyance roller, and it is possible to reduce misalignment of joints.

  However, as a cause of the unevenness of the document conveying speed, in addition to the above-described eccentricity and twist of the conveying roller, there is an occurrence of unevenness of feeding due to the slippage of the document in the conveying roller. In this case, as the distance between the front and rear CISs increases, errors due to feed unevenness accumulate, and the seam image shift in the sub-scanning direction tends to increase.

  As for the CIS interval, for example, when the transport roller is φ20 [mm], the integral multiple of the circumference is 62.8 [mm] (1 time) and 125.6 [mm] (2 times). At present, the general CIS width is around 15 [mm]. In this case, the CIS interval is about four times as large as the CIS arrangement interval.

  Therefore, as in the configuration described in Patent Document 1, when the arrangement interval of the front and rear CIS is set to an integral multiple of the circumferential length of the transport roller, the front and rear CIS interval is increased, and feed unevenness due to document slippage in the transport roller is caused. There was a problem that was likely to occur.

  Furthermore, there is a need among users of wide-width image reading apparatuses to store images such as drawings and tracing paper (hereinafter referred to as “trepe”) originals as read data. Among such film and trepe originals, the frictional resistance of the paper is small, and there are many slippery paper types compared to plain paper, and there is a seam misalignment image in the sub-scanning direction due to the original slipping. Likely to happen.

  For this reason, when the front-rear CIS interval is an integral multiple of the roller circumferential length as in the configuration described in Patent Document 1, the front-rear CIS interval is large. Eye image quality tends to be worse. Therefore, in the image reading apparatus described in Patent Document 1, it is necessary to provide restrictions such as the use application and the image quality specifications that are difficult to slip and are limited to plain paper originals.

  SUMMARY An advantage of some aspects of the invention is that it provides an image reading apparatus and an image forming apparatus capable of improving the image quality of an image sensor joint regardless of the type of document. .

  In order to achieve the above object, an image reading apparatus according to the present invention has a configuration for reading an image while moving a document on a plurality of image sensors arranged in a staggered pattern using a conveyance roller. Among the image sensors arranged in the front side, the front side image data read by the front side image sensor arranged on the near side is delayed and aligned with the rear side image data read by the rear side image sensor arranged on the rear side. In an image reading apparatus having an image synthesizing unit to synthesize, a synchronous arrangement in which an arrangement interval of the front side image sensor and the rear side image sensor is arranged to be an integral multiple of a circumferential length of the transport roller, and Instructing means for instructing which of the short-distance arrangement the front-side image sensor and the rear-side image sensor are arranged to be close to each other Driving means for moving the arrangement of the image sensor to either the synchronous arrangement or the short-distance arrangement based on an instruction from the instruction means; and sub-scanning the front side image data and the rear side image data Storage means for storing a delay time of the near-side image data corresponding to each of the synchronous arrangement and the short-range arrangement for synthesizing in the direction, and the image synthesizing means is based on the instruction means Based on the arrangement of the image sensor based on the instruction and the delay time of the near-side image data corresponding to each of the synchronous arrangement or the short-range arrangement, the near-side image data and the rear-side image data are subsidized. It is characterized by combining in the scanning direction.

  According to the present invention, the image quality of the image sensor joint can be improved regardless of the document type.

1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a top view showing a CIS arrangement configuration of the image reading apparatus according to the first embodiment of the present invention. FIG. 2 is a side view showing a CIS arrangement configuration of the image reading apparatus according to the first embodiment of the present invention. FIG. 2 is a block diagram showing a CIS arrangement configuration and a control configuration of the image reading apparatus according to the first embodiment of the present invention. It is a flowchart which shows the process of the image composition of the image reading apparatus which concerns on the 1st Embodiment of this invention. It is a top view which shows the arrangement configuration of CIS of the image reading apparatus which concerns on the 2nd Embodiment of this invention. It is a side view which shows the arrangement configuration of CIS of the image reading apparatus which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the arrangement configuration and control structure of CIS of the image reading apparatus which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows the process of the image synthesis of the image reading apparatus which concerns on the 2nd Embodiment of this invention. It is a top view which shows the arrangement configuration of CIS in the conventional image reading apparatus. It is a side view which shows the arrangement configuration of CIS in the conventional image reading apparatus. It is explanatory drawing which shows the joint gap of the subscanning direction of the read image in the conventional image reading apparatus.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
As shown in FIG. 1, an image forming apparatus 1 according to the present embodiment includes an apparatus main body 1M having a paper feed section 2, an image forming section 3, and an image reading apparatus 4, and an automatic document arranged on the apparatus main body 1M. This is a digital multi-function machine including a transport unit (ADF) 5.

  The paper feeding unit 2 includes a plurality of stages of paper feeding cassettes 21A, 21B, and 21C that can store cut sheet-like transfer papers P in a stacked state. In each of the paper feed cassettes 21A, 21B, and 21C, for example, transfer paper P (for example, white paper) having a sheet size selected in advance from a plurality of sheet sizes is accommodated in the vertical or horizontal paper feeding direction. ing.

  The paper feeding unit 2 includes paper feeding devices 22A, 22B, and 22C that sequentially pick up and separately transfer the transfer paper P stored in the paper feeding cassettes 21A, 21B, and 21C from the uppermost layer side. The paper feeding unit 2 is further provided with various rollers 23 and the like. By these, the transfer paper P fed from the paper feeding devices 22A, 22B, and 22C is transferred to a predetermined image forming position of the image forming unit 3. A sheet feeding path 24 is formed to convey the sheet.

  The image forming unit 3 includes an exposure device 31, photosensitive drums 32K, 32Y, 32M, and 32C, and a developing device filled with black (K), yellow (Y), magenta (M), and cyan (C) toners. 33K, 33Y, 33M, and 33C. The image forming unit 3 includes a primary transfer unit 34, a secondary transfer unit 35, and a fixing unit 36.

  For example, the exposure device 31 generates the laser light L for exposure of each color based on the image read by the image reading device 4. Further, the exposure device 31 exposes the photosensitive drums 32K, 32Y, 32M, and 32C of the respective colors with laser light, and the static layers of the respective colors corresponding to the read images on the surface layer portions of the photosensitive drums 32K, 32Y, 32M, and 32C. An electrostatic latent image is formed.

  The developing devices 33K, 33Y, 33M, and 33C supply the thin-layer toner to the corresponding photosensitive drums 32K, 32Y, 32M, and 32C, respectively, and develop the electrostatic latent image with the toner. Is supposed to do.

  The image forming unit 3 primarily transfers the toner image developed on the photosensitive drums 32K, 32Y, 32M, and 32C to the primary transfer unit 34, and the toner image is transferred to the secondary transfer unit 35 adjacent to the primary transfer unit 34. Secondary transfer is performed on the transfer paper P. Further, the image forming unit 3 heats and pressurizes the toner image secondarily transferred onto the transfer paper P and melts it, and fixes the color image on the transfer paper P for recording.

  The image forming unit 3 has a transport path 39A for transporting the transfer paper P carried from the paper feed unit 2 through the paper feed path 24 to the secondary transfer unit 35 side. In the transport path 39A, first, the transport timing and transport speed of the transfer paper P are adjusted by the registration roller pair 37. The transfer sheet P passes through the secondary transfer unit 35 and the fixing unit 36 in synchronization with the belt speed at the primary transfer unit 34 and the secondary transfer unit 35 and is then discharged onto the discharge tray 38. It is like that.

  The image forming unit 3 also has a manual paper feed path 39B that feeds transfer paper (not shown) placed on the manual feed tray 25 to the transport path 39A upstream of the registration roller pair 37. ing.

  Below the secondary transfer unit 35 and the fixing unit 36, a switchback conveyance path 39C and a reverse conveyance path 39D each including a plurality of conveyance rollers and conveyance guides are disposed.

  When forming an image on both sides of the transfer paper P, the switchback transport path 39C moves backward after moving the transfer paper P on which one side of the image has been fixed from one end (moves in the opposite direction to the time of entry). ) To carry out switchback.

  The reverse conveyance path 39D reverses the front and back of the transfer paper P that is switched back by the switchback conveyance path 39C, and feeds the paper again to the registration roller pair 37.

  The transfer paper P that has been subjected to the image fixing process on one side by the switchback conveyance path 39C and the reverse conveyance path 39D is reversed in its forward and reverse directions, and again enters the secondary transfer nip. . The transfer paper P is discharged onto the paper discharge tray 38 after the secondary transfer processing and fixing processing of the image are performed on the other surface.

  The image reading device 4 includes a first carriage 41 on which a light source and a mirror member are mounted, a second carriage 42 on which a mirror member is mounted, an imaging lens 43, an imaging unit 44, and a contact glass 106. These are arranged on the apparatus main body 1M side and constitute a first surface reading unit 40 that reads an image on one image surface (for example, the front image surface) of the document sheet S conveyed on the contact glass 106. The first surface referred to here is one surface of the automatically conveyed document sheet S, for example, the front image surface.

  The image reading device 4 is provided with a contact glass 46 on which the document sheet S is placed, and an abutting member 47a that can abut and position one side of the document sheet S.

  The first carriage 41 is provided below the contact glass 106 and the contact glass 46 so as to be movable in the left-right direction and to be position-controllable in the drawing, and reflects the illumination light from the light source by the mirror member to expose the exposure surface The side can be irradiated. The reflected light reflected by the document sheet S is imaged by the imaging lens 43 via the mirror members mounted on the first carriage 41 and the second carriage 42, and the image formed by the imaging unit 44 is formed. It can be read.

  The image reading device 4 performs exposure scanning on the image surface of the document sheet S placed on the contact glass 46 while moving the first carriage 41 and the second carriage 42 at a speed ratio of, for example, 2: 1 with the light source turned on. Can be done. The image reading device 4 can perform a fixed document reading function (so-called flatbed scanner function) by reading a document image by the imaging unit 44 during the exposure scanning.

  The image reading device 4 can stop the first carriage 41 at a fixed position directly below the contact glass 106. The image reading device 4 has a moving document reading function (so-called DF scanner function) that reads an image on the first surface of the document sheet S during automatic document conveyance without moving an optical system including a light source and a reflection mirror. It can be demonstrated.

  Further, the image forming apparatus 1 has a second surface reading unit 48 built in the automatic document feeder 5 side in addition to the first surface reading unit 40 in the image reading device 4. The second surface reading unit 48 scans the second surface of the document sheet S after passing over the contact glass, for example, the image surface on the back side.

  The automatic document feeder 5 is connected to the upper part of the apparatus main body 1M of the image forming apparatus 1 through a hinge mechanism so as to be opened and closed. The automatic document feeder 5 is rotated between an open position where the contact glass 106 and the contact glass 46 are exposed in the image reading apparatus 4 and a closed position where the contact glass 106 and the contact glass 46 are covered. Yes.

  The automatic document feeder 5 is configured as a sheet-through type automatic document feeder. The automatic document transport unit 5 includes a document table 51 that is a document placement table, a document transport unit 52 including various rollers and guide members, and a document discharge tray 53 that stacks document sheets S after image reading. Yes.

  FIG. 2 is a top view showing the configuration of the CIS arrangement switching mechanism 200 of the image reading apparatus 4 according to the present embodiment, and FIG. 3 is a side view. An example in which a CIS is used as an image sensor will be described. Although this embodiment shows a case where five CISs are arranged, the number of CISs arranged is not necessarily limited to this.

  The CIS arrangement switching mechanism 200 includes CISs 101 to 105, a CIS unit driving mechanism 503, a base frame 501, an operation unit 712, a CPU 711, a RAM 714, and an image processing unit 704, which will be described later. The CIS unit driving mechanism 503 constitutes driving means according to the present invention, and the image processing unit 704 constitutes image synthesizing means according to the present invention. Further, the CPU 711 constitutes an instruction unit according to the present invention. The RAM 714 constitutes storage means according to the present invention.

  The CIS 101, CIS 103, and CIS 105 are disposed on the front side in the sub scanning direction below the contact glass 106, and the CIS 102 and CIS 104 are disposed on the rear side in the sub scanning direction. Hereinafter, CIS101, CIS103, and CIS105 are also referred to as front side CIS, and CIS102 and CIS104 are also referred to as rear side CIS below.

  CIS101, CIS103, and CIS105 each constitute a front image sensor according to the present invention, and CIS102 and CIS104 each constitute a rear image sensor according to the present invention. CIS101, CIS103, and CIS105 constitute a front image sensor group according to the present invention as a whole, and CIS102 and CIS104 constitute a rear image sensor group as a whole according to the present invention.

  An image read by the near-side image sensor is referred to as near-side image data, and an image read by the back-side image sensor is referred to as back-side image data.

  The CIS 101, CIS 103, and CIS 105 are arranged adjacent to each other on the sub-scanning position C with a predetermined interval in the main scanning direction. The CISs 102 and 104 are arranged adjacent to each other on the sub-scanning position A or the sub-scanning position B with a predetermined interval in the main scanning direction, and the CISs 101 to 105 are arranged in a staggered manner as a whole. Each CIS reads an image on the original sheet S conveyed between the conveying rollers 107 and 108.

  Hereinafter, a configuration in which the CIS 102 and CIS 104 are arranged on the sub-scanning position A is referred to as a synchronous arrangement, and a configuration in which the CIS 102 and CIS 104 are arranged on the sub-scanning position B is referred to as a short distance arrangement.

  The interval Y (A) between the sub-scanning positions A and C when the rear CISs 102 and 104 are arranged in the same row at the sub-scanning position A is an integral multiple of the circumferential length of the transport rollers 107 and 108. The reason for the integral multiple is to reduce unevenness in conveyance due to the eccentricity of the conveyance roller and to obtain a high-quality image with small seam deviation.

  The rear CIS can be arranged in the same row at the sub-scanning position B shown in FIG. 2, and the interval Y (B) between the sub-scanning positions B and C is shorter than the interval Y (A), and the front CIS row And the rear CIS row are arranged close to a position where they can be arranged without contact. The short-distance arrangement allows the film and trepe modes that are prone to slip to be installed and instructed, and the gap between the front and rear CIS is reduced to reduce the seam shift due to the slippage of the original document. This is to reduce image quality deterioration due to shift. In this case, since the arrangement interval of the front and rear CIS is not an integral multiple of the roller circumferential length, the influence of uneven conveyance due to roller eccentricity is more easily affected than in the case of synchronous arrangement, but the influence is compared because the CIS interval is a short distance. Therefore, it is possible to obtain a good image quality.

  In this embodiment, the distance in the sub-scanning direction between the front side CIS and the rear side CIS when synchronously arranged is 40.78 mm, which is a distance corresponding to one rotation of the conveyance roller, but is not necessarily limited to this distance. Absent. Further, the diameters of the conveying rollers 107 and 108 are 12.98 mm, and the document conveying speed is 80 mm / s. However, the values are not necessarily limited to these values.

  In addition, the distance in the sub-scanning direction between the near side CIS and the back side CIS when arranged at a short distance is 19.8 mm, but is not necessarily limited to this distance. This distance is determined by the restriction of the outer diameter of the rear CIS. If the CIS has a small outer diameter, the distance can be further reduced to a distance where the CISs do not interfere with each other.

  As shown in FIG. 3, a rear CIS is installed on one base frame 501 and integrated as a rear CIS unit 601. The reference white plate 201 is provided to face the contact glass 106.

  The CIS unit driving mechanism 503 includes a rack and pinion and the like. The CIS unit driving mechanism 503 generates a driving force by a stepping motor or rotation driven by a manual lever, and a position at which the base frame 501 provided with the rear CIS is disposed at the sub-scanning position A or B together with the rear CIS unit 601. It is possible to change the position of the arrangement.

  The movement of the moving rear CIS together with the base frame 501 of the same member suppresses the occurrence of positional accuracy errors between the CISs due to the movement, and makes it possible to ensure highly accurate joint image quality. Because. As a result, the drive configuration for moving the CIS can be simplified, and the number of parts, cost, and product size can be easily reduced.

  In the present embodiment, a total of three CISs CIS101, 103, and 105 are arranged on the front side, and a total of two CISs CIS102 and 104 are arranged on the rear side. Although the CIS 102 and 104 are configured to be movable by the CIS unit driving mechanism 503, the CIS that can be moved is not necessarily limited thereto. The reason for this configuration is to simplify the configuration and reduce the cost by making the moving CIS row only one side of the front and rear rows. Further, by reducing the number of CISs that move, the accumulation of positional accuracy errors due to movement is reduced, and a higher-accuracy quality image can be acquired.

  FIG. 4 is a block diagram showing an image composition process in the image reading apparatus 4 according to this embodiment.

  In FIG. 4, for simplification of description, the front CIS sequence is represented by two CIS101 and CIS103, and the rear CIS sequence is represented by one CIS102. The same shall apply to cases of more than that.

  In the apparatus main body 1M of the image forming apparatus 1, an operation unit 712 having a print key, a touch panel, and the like is installed at a position that can be easily used by a user such as an upper surface. An instruction button 713 for instructing whether to use plain paper or special paper is provided on the operation unit 712, and the user can select either plain paper or special paper (slipper paper such as film or trepe). It tells you if you want to use the manuscript. The instruction button 713 constitutes an instruction unit according to the present invention.

  The CPU 711 changes the distance Y between the front side CIS and the rear side CIS by moving the rear side CIS unit 601 back and forth via the CIS unit drive mechanism 503 according to the instruction content by the operation unit 712. It is supposed to be. Specifically, when the use of plain paper is instructed by the operation unit 712, the synchronous arrangement is used, and when the use of special paper is instructed, the short-range arrangement is used. Thereby, the CPU 711 can switch the arrangement position of the rear CIS unit 601 between the sub-scanning position A (synchronous arrangement) and the sub-scanning position B (short-distance arrangement) shown in FIG.

  Image data read by the CIS 101 to 103 is stored in memories 705 to 707 in the image processing unit 704 through A / D converters 701 to 703, respectively. The CPU 711 controls the image processing unit 704. The image data stored in the memories 705 to 707 is subjected to shading processing, which is a known technique, by the shading correction unit 708, and the sub-scan joint correction unit 709 is performed. Send image data.

  The CPU 711 corrects the delay time stored in advance in the RAM 714 in accordance with the paper type mode instructed by the plain paper / special paper instruction button 713, and receives the image data received by the sub-scan joint correction unit 709. The images are connected to form a read image 710.

  In the RAM 714, a synchronous arrangement delay time t1 that is a delay time of the rear CIS with respect to the front CIS when the rear CIS is synchronously arranged, and a rear side with respect to the front CIS when the rear CIS is arranged at a short distance A short-distance placement delay time t2 which is a CIS delay time is stored.

  Here, the delay time t1 is about 0.51 seconds, and the inter-CIS distance Y (A) is the time for moving the document. The delay time t2 is about 0.24, and the inter-CIS distance Y (B) is set as the time for moving the document. The delay times t1 and t2 are not necessarily limited to these times, and may be other times.

  The CPU 711 selects the delay times t1 and t2 according to the instruction of the plain paper / special paper instruction button 713, and executes the joint correction process.

  The image processing unit 704 delays the near-side image data read by the near-side CIS arranged on the near side, and combines it with the rear-side image data read by the rear-side CIS arranged on the rear side. ing. The image processing unit 704 synthesizes the near side image data and the back side image data in the sub-scanning direction based on the arrangement of each CIS by the instruction button 713 and the delay times t1 and t2 of the near side image data at the time of image synthesis. It has become.

  FIG. 5 is a flowchart showing the image composition process of the image reading apparatus 4 according to the present embodiment. The image composition processing will be described below with reference to FIG.

  First, the user selects either a plain paper mode for passing plain paper or a special paper mode for passing special paper using the instruction button 713 of the operation unit 712 (step S1).

  When the plain paper mode is selected, the CPU 711 causes the CIS unit driving mechanism 503 to move the rear side CIS unit 601 to the position of the synchronous arrangement (step S2).

  When the special paper mode is selected, the CPU 711 causes the CIS unit drive mechanism 503 to move the rear side CIS unit 601 to the position of the short distance arrangement (step S3).

  After the rear-side CIS unit 601 is arranged synchronously or at a short distance in step S1 or step S2, the document S is passed through the image reading apparatus 4 through the conveyance rollers 107 and 108 (step S4).

  Each of the CISs 101 to 105 reads a passed document, and the read image data is temporarily stored in a memory corresponding to each CIS. In the example of FIG. 4, the CIS 101 data is temporarily stored in the memory 705, the CIS 102 data is temporarily stored in the memory 706, and the CIS 103 data is temporarily stored in the memory 707 (step S5).

  The shading correction unit 708 performs shading correction on the data stored in the memories 705 to 707 (step S6).

  Next, the CPU 711 instructs the sub-scanning seam correction unit 709 which delay time for synchronous placement or short-range placement is used for image composition based on the paper type mode selected in step S1 (step S7).

  When the plain paper mode is selected, the rear CIS unit 601 is synchronously arranged, and the image processing unit 704 outputs the image of each CIS corrected using the synchronous arrangement delay time t1 stored in the RAM 714. The images are combined (step S8), and the read image is output (step S10).

  When the special paper mode is selected, the rear CIS unit 601 is arranged at a short distance, and the image processing unit 704 corrects each CIS corrected using the short distance arrangement delay time t2 stored in the RAM 714. The images are combined (step S9), and the read image is output (step S10).

  As described above, the image reading device 4 according to the present embodiment has a configuration in which an image is read on the CISs 101 to 105 arranged in a staggered manner while moving the document using the transport rollers 107 and 108, Among the CISs 101 to 105, an image processing unit that delays the near-side image data read by the near-side CIS arranged on the near side and combines it with the rear-side image data read by the rear-side CIS arranged on the rear side. 704 is provided.

  In addition, the image reading device 4 according to the present embodiment includes an instruction button 713 for instructing whether an arrangement interval between the front side CIS and the rear side CIS is a synchronous arrangement or a short-distance arrangement. Based on an instruction from the instruction button 713, a CIS unit drive mechanism 503 for moving the arrangement of the CISs 101 to 105 to either a synchronous arrangement or a short-distance arrangement, and a front corresponding to each arrangement of the synchronous arrangement and the short-distance arrangement And a RAM 714 that stores the delay time of the side image data.

  In addition, the image processing unit 704 in the image reading apparatus 4 according to the present embodiment displays the near-side image data corresponding to the arrangement of the CISs 101 to 105 based on the instruction by the instruction button 713 and the arrangement of the synchronous arrangement or the short-range arrangement. Based on this delay time, the near side image data and the back side image data are combined in the sub-scanning direction.

  With the above configuration, in the read image of a plain paper original that is difficult to slip, the front side CIS and the rear side CIS are arranged to synchronize the original conveyance speed unevenness due to the eccentricity or twisting of the conveyance rollers 107 and 108, thereby connecting the CIS joints. High image quality can be achieved. In addition, even for slippery special paper originals such as film and trepe, the CIS joint image is formed by arranging the front side CIS and the rear side CIS at a short distance from each other in the sub-scanning direction due to the original slippage. Thus, it is possible to obtain a read image with high joint image quality for both plain paper and a sliding original. Therefore, the image quality of the CIS joint can be improved regardless of the document type.

  Further, only the CIS group on the side having a smaller number of CISs among the front side CIS group including the front side CIS and the rear side CIS group including the rear side CIS may be movable.

  With this configuration, it is possible to simplify the configuration and reduce the cost by making the moving CIS row only one side of the front and rear rows. Also, by reducing the number of CISs that move, the accumulation of positional accuracy errors due to movement can be reduced, and more accurate image quality can be acquired.

  Further, the CISs 102 and 104 whose arrangement is moved by the CIS unit driving mechanism 503 may be mounted on the base frame 501 so that the base frame 501 can be moved to the position of the synchronous arrangement or the short distance arrangement.

  With this configuration, since the moving CIS row is moved together with the base frame 501 of the same member, occurrence of positional accuracy errors between the CISs due to movement can be suppressed, and high-accuracy joint image quality can be ensured. Further, the configuration of the CIS unit driving mechanism 503 for moving the CIS is simplified, and the number of parts, the cost, and the product size can be easily reduced.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS.

  This embodiment is different from the first embodiment in that the rear side CIS is not movable and the rear extension CISs 906 and 907 can be arranged, but other configurations are basically the same. is there. Therefore, the same components will be described using the same reference numerals as those in the first embodiment shown in FIGS. 1 to 5, and only differences will be described in detail.

  FIG. 6 is a top view showing the configuration of the CIS extension mechanism 300 of the image reading apparatus 4 according to the present embodiment, and FIG. 7 is a side view. An example in which the CIS is used for the image sensor will be described. Although this embodiment shows a case where five CISs are arranged, the number of CISs arranged is not necessarily limited to this.

  The CIS extension mechanism 300 includes CISs 101 to 105, rear extension CISs 906 and 907, a base frame 901, an operation unit 712, a CPU 711, a RAM 714, and an image processing unit 704, which will be described later. The image processing unit 704 constitutes an image composition unit according to the present invention. The rear extension CISs 906 and 907 constitute an additional image sensor according to the present invention.

  The CIS 101, CIS 103, and CIS 105 are disposed on the front side in the sub scanning direction below the contact glass 106, and the CIS 102 and CIS 104 are disposed on the rear side in the sub scanning direction. Further, the rear extension CISs 906 and 907 can be additionally arranged on the rear side in the sub-scanning direction of the CIS101, CIS103, and CIS105 and on the front side of the CIS102 and 104. CIS101, CIS103, and CIS105 are hereinafter also referred to as front CIS, and CIS102, CIS104, CIS906, and CIS907 are also referred to as rear CIS below.

  CIS101, CIS103, and CIS105 each constitute a front image sensor according to the present invention, and CIS102, CIS104, CIS906, and CIS907 each constitute a rear image sensor according to the present invention. CIS101, CIS103, and CIS105 constitute a front image sensor group according to the present invention as a whole, and CIS102 and CIS104 constitute a rear image sensor group as a whole according to the present invention. Further, the rear extension CIS 906 and CIS 907 constitute an additional image sensor group according to the present invention as a whole.

  An image read by the near-side image sensor is referred to as near-side image data, and an image read by the back-side image sensor is referred to as back-side image data.

  The CIS 101, CIS 103, and CIS 105 are arranged adjacent to each other on the sub-scanning position C with a predetermined interval in the main scanning direction. The CISs 102 and 104 are arranged adjacent to each other on the sub-scanning position A with a predetermined interval in the main scanning direction, and the CISs 101 to 105 are arranged in a staggered manner as a whole. Each CIS reads an image on the original sheet S conveyed between the conveying rollers 107 and 108.

  Hereinafter, a configuration in which the CIS 102 and CIS 104 are arranged on the sub-scanning position A is referred to as a synchronous arrangement, and a configuration in which the CIS 906 and CIS 907 are arranged on the sub-scanning position B is referred to as a short distance arrangement.

  The interval Y (A) between the sub-scanning positions A and C when the rear CISs 102 and 104 are arranged in the same row at the sub-scanning position A is an integral multiple of the circumferential length of the transport rollers 107 and 108. The reason for the integral multiple is to reduce unevenness in conveyance due to the eccentricity of the conveyance roller and to obtain a high-quality image with small seam deviation.

The rear CIS can be additionally arranged in the same row at the sub-scanning position B shown in FIG. 6, and the interval Y (B) between the sub-scanning positions B and C is shorter than the interval Y (A). The rear side CIS row is arranged close to a position where it can be arranged without contact. The configuration that can be additionally arranged is
This is because, unlike the first embodiment, the positional accuracy error due to the movement of the CIS sequence is reduced by eliminating the movement of the CIS sequence. It is also for reducing the number of parts used, realizing resource saving and cost reduction, and facilitating installation work time.

  In this embodiment, the distance in the sub-scanning direction between the front side CIS and the rear side CIS when synchronously arranged is 40.78 mm, which is a distance corresponding to one rotation of the conveyance roller, but is not necessarily limited to this distance. Absent. Further, the diameters of the conveying rollers 107 and 108 are 12.98 mm, and the document conveying speed is 80 mm / s. However, the values are not necessarily limited to these values.

  In addition, the distance in the sub-scanning direction between the near side CIS and the back side CIS when arranged at a short distance is 19.8 mm, but is not necessarily limited to this distance. This distance is determined by the restriction of the outer diameter of the rear CIS. If the CIS has a small outer diameter, the distance can be further reduced to a distance where the CISs do not interfere with each other.

  As shown in FIG. 7, the CISs 102 and 104 are integrated as a rear CIS unit 601 for plain paper by being installed on the same base frame 501. The reference white plate 201 is provided to face the contact glass 106.

  Further, the rear extension CISs 906 and 907 are installed on the same base frame 901 so as to be integrated as the rear extension CIS unit 902 and can be additionally arranged together with the rear extension CIS unit 902. The reason why such a configuration is adopted is that a plurality of CISs are integrated to facilitate the attaching / detaching operation and shorten the operation time. Further, since the integrated rear extension CIS unit 902 is attached / detached, the variation in misalignment error of each CIS accompanying attachment / detachment is reduced, and the image quality of the joint misalignment is stabilized.

  The rear extension CIS unit 902 can be placed at the equal sub-scanning position B in FIG. 6 together with the base frame 901 using fastening means such as screws, and the interval Y (B) between the sub-scanning positions B and C is The front side CIS row and the rear extension CIS row are arranged close to each other so as to be arranged without contact with each other, shorter than the interval Y (A).

  In the present embodiment, a total of three CISs CIS101, 103, and 105 are arranged on the front side, and a total of two CISs CIS102 and 104 are arranged on the rear side. Although the rear extension CIS unit 902 is arranged, the side where the rear extension CIS unit 902 is arranged is not necessarily limited thereto. The reason for this configuration is to reduce the number of optional parts, reduce the number of mounting work steps, and realize resource saving and cost reduction.

  FIG. 8 is a block diagram showing an image composition process in the image reading apparatus 4 according to this embodiment.

  In FIG. 8, for simplification of description, the front CIS sequence is represented by two CIS101 and CIS103, and the rear CIS sequence is represented by one CIS102. The same shall apply to cases of more than that.

  In the apparatus main body 1M of the image forming apparatus 1, an operation unit 712 having a print key, a touch panel, and the like is installed at a position that can be easily used by a user such as an upper surface. An instruction button 713 for instructing whether to use plain paper or special paper is provided on the operation unit 712, and the user can select either plain paper or special paper (slipper paper such as film or trepe). It tells you if you want to use the manuscript. The instruction button 713 constitutes an instruction unit according to the present invention. The CPU 711 constitutes an instruction unit and a determination unit according to the present invention. The RAM 714 constitutes storage means according to the present invention.

  The CPU 711 outputs image data obtained by any of the CIS units of the rear CIS unit 601 for plain paper and the rear additional CIS unit 902 for special paper according to the content of the operation unit 712 by the image processing unit 704. Judge whether to use for synthesis. As a result, the CPU 711 can switch between using the CIS unit arranged at the sub-scanning position A (synchronous arrangement) and the sub-scanning position B (short-distance arrangement) shown in FIG.

  The image data read by the CISs 101 to 103 and the rear extension CISs 906 and 907 are stored in the memories 705 to 707 in the image processing unit 704 through the A / D converters 701 to 703, respectively. The CPU 711 controls the image processing unit 704. The image data stored in the memories 705 to 707 is subjected to shading processing, which is a known technique, by the shading correction unit 708, and the sub-scan joint correction unit 709 is performed. Send image data.

  The CPU 711 corrects the delay time stored in advance in the RAM 714 in accordance with the paper type mode instructed by the plain paper / special paper instruction button 713, and receives the image data received by the sub-scan joint correction unit 709. The images are connected to form a read image 710.

  In the RAM 714, there is a delay time t1 that is a delay time of the rear CIS unit 601 that is synchronously arranged with respect to the front side CIS, and a short distance placement delay that is a delay time of the rear extension CIS unit 902 with respect to the front side CIS. Time t2 is stored.

  Here, the delay time t1 is about 0.51 seconds, and the inter-CIS distance Y (A) is the time for moving the document. The delay time t2 is about 0.24, and the inter-CIS distance Y (B) is set as the time for moving the document. The delay times t1 and t2 are not necessarily limited to these times, and may be other times.

  The CPU 711 selects the delay times t1 and t2 according to the instruction of the plain paper / special paper instruction button 713, and executes the joint correction process.

  The image processing unit 704 delays the near-side image data read by the near-side CIS arranged on the near side, and combines it with the rear-side image data read by the rear-side CIS arranged on the rear side. ing. The image processing unit 704 synthesizes the near side image data and the back side image data in the sub-scanning direction based on the arrangement of each CIS by the instruction button 713 and the delay times t1 and t2 of the near side image data at the time of image synthesis. It has become.

  FIG. 9 is a flowchart showing an image composition process of the image reading apparatus 4 according to the present embodiment, and the image composition process will be described below with reference to FIG.

  First, the document S is passed through the image reading device 4 through the conveying rollers 107 and 108 (step S11). Next, the CPU 711 determines whether the user has selected the normal paper mode for passing plain paper or the special paper mode for passing special paper with the instruction button 713 (step S12).

  Each of the CISs 101 to 105 reads the passed document S, and the read image data is temporarily stored in a memory corresponding to each CIS. When the plain paper mode is selected, the image data read by the front CIS and the rear CIS unit 601 is temporarily stored in a memory corresponding to each CIS. In the example of FIG. 7, the CIS 101 data is temporarily stored in the memory 705, the CIS 102 data is temporarily stored in the memory 706, and the CIS 103 data is temporarily stored in the memory 707 (step S12).

  If the special paper mode is selected, the image data read by the front CIS and the rear extension CIS unit 902 are similarly temporarily stored in the memory corresponding to each CIS (step S13).

  The shading correction unit 708 performs shading correction on the data stored in the memories 705 to 707 (step S14).

  Next, the CPU 711 instructs the sub-scanning seam correction unit 709 which delay time for synchronous placement or short-range placement is used for image composition based on the paper type mode selected in step S1 (step S15).

  When the plain paper mode is selected, the rear CIS unit 601 is synchronously arranged, and the image processing unit 704 combines the images of each CIS corrected using the synchronous arrangement delay time t1 stored in the RAM 714. (Step S17), and the read image is output (Step S19).

  When the special paper mode is selected, the rear extension CIS unit 902 is arranged at a short distance, and the image processing unit 704 corrects each CIS corrected using the short distance arrangement delay time t2 stored in the RAM 714. The images are combined (step S18), and the read image is output (step S19).

  As described above, the image reading device 4 according to the present embodiment has a configuration in which an image is read on the CISs 101 to 105 arranged in a staggered manner while moving the document using the transport rollers 107 and 108, Among the CISs 101 to 105, an image processing unit that delays the near-side image data read by the near-side CIS arranged on the near side and combines it with the rear-side image data read by the rear-side CIS arranged on the rear side. 704, and is arranged synchronously so that the arrangement interval between the front CIS and the rear CIS is an integral multiple of the circumferential length of the transport rollers 107 and 108.

  In addition, there are a front CIS in which the arrangement interval in the sub-scanning direction with the front CIS is synchronously arranged, and rear extension CISs 906 and 907 additionally arranged so as to be closer than the arrangement interval of the rear CIS. An instruction button 713 for instructing whether image data obtained using the rear side CIS and the rear extension CISs 906 and 907 additionally arranged are used for image synthesis with the near side image data, and instructions by the instruction button 713 The CPU 711 for determining whether the image data obtained using the rear CIS or the rear extension CIS 906 or 907 is used for image synthesis with the front image data, and the front image data and the rear image data or the rear extension Delay time of near side image data according to CIS used to synthesize image data by CIS 906 and 907 It has a memorized RAM 714, a.

  Further, the image processing unit 704 combines the near-side image data and either the back-side image data or the image data based on the rear extension CIS 906 or 907 in the sub-scanning direction based on the delay time of the near-side image data. It has become.

  With this configuration, the rear extension CISs 906 and 907 can be additionally arranged according to the document type, thereby eliminating the movement of the rear CIS row and reducing the positional accuracy error due to the movement of the CIS row. Therefore, the image quality of the image sensor joint can be improved regardless of the document type.

  In addition, the rear extension CIS 906 and 907 are optional products and can be retrofitted so that only necessary users can be provided to suppress and use redundant functions and configurations in standard products without options. Resource saving and cost reduction can be realized by reducing the number of parts.

  Further, the rear extension CISs 906 and 907 may be additionally arranged only on the side with a smaller number of sensors in the front side CIS group including the front side CIS and the rear side CIS group including the rear side CIS.

  With this configuration, it is possible to reduce the number of optional parts, reduce the number of installation work steps, save resources, and reduce costs.

  Further, an additional CIS group composed of rear extension CISs 906 and 907 to be additionally arranged may be mounted on one base frame 901 so that the additional arrangement can be made for each base frame 901 at a position to be additionally arranged.

  With this configuration, the plurality of rear extension CISs 906 and 907 are integrated to form the rear extension CIS unit 902, thereby facilitating attachment / detachment work and shortening the work time. In addition, since the integrated rear extension CIS unit 902 is attached and detached, variations in misalignment of the rear extension CISs 906 and 907 accompanying the attachment and detachment can be reduced, and the image quality of joint misalignment can be stabilized.

  According to the present invention, the image quality at the joint of the image sensor can be improved regardless of the document type, and it is useful for image reading apparatuses and image forming apparatuses in general.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 4 Image reader 101-105 CIS (image sensor)
107, 108 Transport roller 501 Base frame 503 CIS unit drive mechanism (drive means)
704 Image processing unit (image composition means)
711 CPU (instruction means, determination means)
713 Instruction button (instruction means)
714 RAM (storage means)
906, 907 Rear extension CIS (additional image sensor)
S Document t1, t2 Delay time

Japanese Patent Laid-Open No. 11-027477

Claims (7)

A plurality of image sensors arranged in a staggered pattern are configured to read an image while moving a document using a conveyance roller, and among the image sensors arranged in a staggered pattern, the front side disposed on the near side In the image reading apparatus having an image synthesizing unit that delays the near-side image data read by the side image sensor and combines it with the rear-side image data read by the rear-side image sensor arranged on the rear side.
Synchronous arrangement in which the arrangement interval of the front image sensor and the rear image sensor is arranged to be an integral multiple of the circumferential length of the transport roller, and the front image sensor and the rear image sensor are close to each other. Instructing means for instructing which one of the short-distance arrangements to arrange to be a distance;
Driving means for moving the image sensor to switch to either the synchronous arrangement or the short-range arrangement based on an instruction by the instruction means;
Storage means for storing delay times of the near-side image data corresponding to each of the synchronous arrangement and the short-range arrangement for synthesizing the near-side image data and the rear-side image data in a sub-scanning direction; Have
The image synthesizing unit is configured to generate the near-side image based on a delay time of the near-side image data corresponding to the arrangement of the image sensor based on an instruction from the instruction unit and each of the synchronous arrangement or the short-distance arrangement. An image reading apparatus characterized by combining data and the rear image data in a sub-scanning direction.   Of the front side image sensor group consisting of the front side image sensor and the rear side image sensor group consisting of the rear side image sensor, only the image sensor group on the side with a small number of image sensors included can be moved. The image reading apparatus according to claim 1, wherein:   2. The image sensor that is moved by the driving means is mounted on a single base frame, and can be moved together with the base frame to the position of the synchronous arrangement or the short-distance arrangement. Alternatively, the image reading apparatus according to claim 2. A plurality of image sensors arranged in a staggered pattern are configured to read an image while moving a document using a conveyance roller, and among the image sensors arranged in a staggered pattern, the front side disposed on the near side Image synthesizing means for delaying the near-side image data read by the side image sensor and synthesizing it in a row with the rear-side image data read by the rear-side image sensor arranged on the rear side;
In the image reading apparatus in which the arrangement interval of the front side image sensor and the rear side image sensor is synchronously arranged so as to be an integral multiple of the circumferential length of the transport roller,
An additional image sensor that is additionally arranged so that an arrangement interval in the sub-scanning direction with the near-side image sensor is closer to the near-side image sensor than the arrangement interval of the rear-side image sensor; ,
Instructing means for instructing which image data obtained by using either the rear-side image sensor arranged in synchronization or the additional image sensor arranged additionally is used for image composition with the near-side image data;
Determining means for determining whether to use image data obtained by using either the rear image sensor or the additional image sensor for image synthesis with the near-side image data based on an instruction by the instruction means;
Storage means for storing a delay time of the near-side image data corresponding to the image sensor used for synthesizing the near-side image data and the back-side image data or the image data by the additional image sensor,
The image synthesizing unit synthesizes the near-side image data and either the back-side image data or the image data obtained by the additional image sensor in the sub-scanning direction based on the delay time of the near-side image data. A characteristic image reading apparatus.   The additional image sensor can be additionally arranged only on a side having a small number of sensors among a front side image sensor group including the front side image sensor and a rear side image sensor group including the rear side image sensor. The image reading apparatus according to claim 4.   The additional image sensor group including the additional image sensors to be additionally arranged is mounted on one base frame, and can be additionally arranged for each base frame at the position to be additionally arranged. Item 6. The image reading apparatus according to any one of Items 5 to 6.   An image forming apparatus comprising the image reading apparatus according to claim 1.

Images