Image forming apparatus and image forming method

Abstract

To provide an image forming apparatus that is prevented from erroneously recognizing dirt attached to a background member as an image, and thereby can form an accurate image.SOLUTION: An image forming apparatus comprises: an image forming unit for forming an image on a recording medium; a reading device that reads an image formation surface of the recording medium on which the image is formed; a background member that is arranged as a base of the recording medium when the reading device reads the image formation surface of the recording medium; and a cleaning unit for cleaning the background member.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus and an image forming method. [Background technology]

[0002] The image forming apparatus includes a reading device for reading an image formed on a recording medium. In this image forming apparatus, each unit related to image formation is controlled based on the read value of the test image read by the reading device. In addition, the read value of the test image by the reading device is subjected to shading correction based on the read value of the reference white member read by the reading device. The reference white member has a reference white portion for acquiring reference data for shading correction. As a technology related to an image forming apparatus including such a reading device, there is a technology disclosed in the following Patent Document 1. This Patent Document 1 describes a technology in which the reference white member is read multiple times by the reading means while at least one of the reading means and the reference white member is moved by the moving means in a direction perpendicular to the sheet conveying direction. It is said that this makes it possible to distinguish and detect dirt on the reference white member from dirt on the reading means. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-267801 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, when an image formed on a recording medium is read by a reading device, a background member is placed on the back side of the recording medium as a base. The reading device reads the background member protruding from both sides of the recording medium as well as the image formed on the recording medium. Furthermore, if the recording medium is made of a material that is optically transparent, the reading device also reads the background member in the portion that overlaps with the recording medium. For this reason, if dirt is attached to the background member, the dirt may be erroneously recognized as a test image. Such erroneous recognition of the test image is a factor that reduces the accuracy of image formation.

[0005] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide an image forming apparatus and an image forming method that are capable of forming images with high accuracy by preventing stains on a background member from being erroneously recognized as an image. [Means for solving the problem]

[0006] In order to achieve this object, the present invention provides an image forming apparatus comprising an image forming unit for forming an image on a recording medium, a reading device for reading the image forming surface of the recording medium on which the image has been formed, a background member arranged as a base for the recording medium when the reading device reads the image forming surface of the recording medium, and a cleaning unit for cleaning the background member. Effect of the Invention

[0007] According to the present invention, it is possible to provide an image forming apparatus and an image forming method that can prevent stains adhering to a background member from being erroneously recognized as an image, thereby enabling highly accurate image formation. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing the overall configuration of an image forming apparatus according to each embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing the main parts of the inspection unit. [Diagram 3] FIG. 3 is a plan view for explaining the configuration of the background member and its surroundings. [Figure 4]FIG. 4 is a side view for explaining the configuration of the background member and its surroundings. [Diagram 5] FIG. 5 is a plan view illustrating an example of a problem caused by dust adhesion to the background member. [Figure 6] FIG. 6 is a side view showing the configuration of the background device according to the first embodiment. [Figure 7] FIG. 7 is a perspective view showing the configuration of the background device according to the first embodiment. [Figure 8] FIG. 8 is a side view showing a background device as a modified example of the first embodiment. [Figure 9] FIG. 9 is a perspective view showing a background device as a modified example of the first embodiment. [Figure 10] FIG. 10 is a diagram showing the replacement of the background member and the shading member. [Figure 11] FIG. 11 shows the signal obtained from the reader when the background material is clean. [Figure 12] FIG. 12 is a diagram showing an example of a signal obtained from a reading device during image formation. [Figure 13] FIG. 13 is a diagram (part 1) for explaining cleaning of the background member in the first embodiment. [Figure 14] FIG. 14 is a diagram (part 2) for explaining cleaning of the background member in the first embodiment. [Figure 15] FIG. 15 is a diagram for explaining an image forming method according to the second embodiment. [Figure 16] FIG. 16 is a side view (part 1) showing the configuration of the background device of the third embodiment. [Figure 17] FIG. 17 is a side view (part 1) showing the configuration of the background device of the third embodiment. [Figure 18] FIG. 18 is a side view showing the configuration of the background device according to the fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each embodiment, elements having substantially the same function or configuration are denoted by the same reference numerals, and duplicated descriptions will be omitted.

[0010] First Embodiment Fig. 1 is a diagram showing the overall configuration of an image forming apparatus according to each embodiment of the present invention. The image forming apparatus 1 shown in Fig. 1 is equipped with an inspection unit 10. In addition to the inspection unit 10, the image forming apparatus 1 is equipped with an image forming unit 20, a recording medium supply unit 30, and a recording medium storage unit 40.

[0011] The image forming unit 20 forms an image on a sheet-like recording medium [r], for example, an electrophotographic type. The recording medium supply unit 30 supplies the recording medium [r] to the image forming unit 20. On the other hand, the recording medium storage unit 40 stores the recording medium [r] on which an image has been formed in the image forming unit 20.

[0012] Here, the recording medium [r] is, for example, long. In this case, the recording medium supply unit 30 includes an unwinder 31 that unwinds the long recording medium [r]. Meanwhile, the recording medium storage unit 40 includes a winder 41 that winds up the long recording medium [r]. A plurality of transport rollers 50 are disposed between the unwinder 31 and the winder 41. The plurality of transport rollers 50, together with the unwinder 31 and the winder 41, constitute a transport mechanism for transporting the recording medium [r] in a predetermined transport direction [FD]. These transport rollers 50 define the travel path of the recording medium [r] between the unwinder 31 and the winder 41, and the recording medium [r] is sequentially wound around them.

[0013] The inspection unit 10 is a section that obtains data for controlling image formation. The inspection unit 10 is disposed between the image forming unit 20 and the recording medium housing unit 40. Such an inspection unit 10 includes a reading device 11 and a background device 12. In addition to these, the inspection unit 10 also includes a shading member 13, a colorimeter 14, and a control unit 15. These are as follows.

[0014] <Reader 11> The reading device 11 captures an image of the main surface of the recording medium [r] discharged from the image forming unit 20. The inspection unit 10 is a line sensor arranged across the conveyance width direction perpendicular to the conveyance direction [FD] of the recording medium [r]. This reading device 11 captures an image of the main surface of the recording medium [r] across the conveyance width direction.

[0015] FIG. 2 is a diagram showing the main parts of the inspection unit 10. As shown in FIG. 2, the reading device 11 includes a light-emitting element 11a, a light-receiving element 11b, and a cover glass 11c. These are arranged across the conveyance width direction that is approximately perpendicular to the conveyance direction [FD] of the recording medium [r]. The light-emitting element 11a is arranged in two directions in the conveyance direction [FD]. Each light-emitting element 11a irradiates the recording medium [r] with inspection light through the cover glass 11c. The light-receiving element 11b receives the inspection light reflected by the recording medium [r] through the cover glass 11c. The light-receiving element 11b converts the intensity of the received inspection light into an electrical signal and transmits it to the control unit 15.

[0016] <Background device 12> The background device 12 is disposed between the two transport rollers 50, facing the cover glass 11c of the reading device 11. A recording medium [r] is placed around the two transport rollers 50 between the cover glass 11c of the reading device 11 and the background device 12. The background device 12 has a background member 12a. The background member 12a is disposed facing the cover glass 11c of the reading device 11 via the recording medium [r].

[0017] The background member 12a is a member that serves as a base when the reading device 11 reads the main surface of the recording medium [r]. The background member 12a includes a black background 120b and a white background 120w that are extended in the transport width direction [CD]. The background device 12 is configured to be movable in the transport direction [FD] by a horizontal drive unit not shown here. This allows the reading device 11 to freely switch the background when capturing an image of the main surface of the recording medium [r] between the black background 120b and the white background 120w.

[0018] The background device 12 also has two rollers 12b, 12b'. The two rollers 12b, 12b' are arranged at positions sandwiching the background member 12a in the transport direction [FD] of the recording medium [r]. The two rollers 12b, 12b' support the recording medium [r] transported in the transport direction [FD] across the transport width direction that is approximately perpendicular to the transport direction [FD]. These rollers 12b, 12b' hold the recording medium [r] in a floating state relative to the background member 12a, and maintain a predetermined distance between the recording medium [r] and the background member 12a.

[0019] FIG. 3 is a plan view for explaining the configuration of the background member 12a and its periphery. FIG. 4 is a side view for explaining the configuration of the background member 12a and its periphery. As shown in FIG. 3 and FIG. 4, the background member 12a is arranged so as to protrude from the end of the recording medium [r] by a sufficient length in the transport width direction [CD] perpendicular to the transport direction [FD] of the recording medium [r]. The reading area [A1] (see FIG. 3) by the reading device 11 includes the entire area of ​​the transport width direction [CD] of the recording medium [r] and the area protruding from the end of the recording medium [r] in the transport width direction [CD].

[0020] Here, the surfaces of the rollers 12b and 12b' are not completely smooth, but have fine irregularities. In addition, when the recording medium [r] is transported in the transport direction [FD], it meanders in the transport width direction [CD] (see FIG. 3). For this reason, when the recording medium [r] is transported, the rollers 12b and 12b' arranged on both sides of the background member 12a rub against the recording medium [r] in the transport direction [FD] and the transport width direction [CD]. As a result, at the contact points between the rollers 12b and 12b' and the recording medium [r], the recording medium [r] is scraped in stripes due to friction with the rollers 12b and 12b', generating dust [d] (paper powder). In addition, when the recording medium [r] is transported, a transport wind [W] (see FIG. 4) is generated on both sides of the recording medium [r] in the transport direction [FD]. As a result, dust [d] generated by friction between the rollers 12b, which are located upstream of the background member 12a in the transport direction [FD], and the recording medium [r] is carried to the background member 12a by the transport air [W] and adheres to the background member 12a.

[0021] The dust [d] generated here is the material that constitutes the back side of the recording medium [r] opposite to the image forming surface that has been scraped off. The recording medium [r] is tack paper, non-tack paper, synthetic paper, etc. Tack paper is configured by bonding a material layer on the image forming surface side and a material layer on the back side with an adhesive layer. The material layer on the image forming surface side is coated paper, high-quality paper, film paper, etc. The material layer on the back side is release paper. It is a base paper made of a uniform material. The synthetic paper is made of a tree-based synthetic material such as Yupo.

[0022] The adhesion of dust [d] to the background member 12a causes the following problems. Fig. 5 is a plan view for explaining an example of a problem caused by the adhesion of dust [d] to the background member 12a. As shown in Fig. 5, when dust [d] adheres within the range of the reading area [A1] of the background member 12a, the dust [d] is read by the reading device 11. When the recording medium [r] is optically transparent, the reading device 11 also reads the dust [d] adhered to the portion overlapping the recording medium [r].

[0023] Here, in addition to the image formed in the image forming area [A], test images such as a register mark [m1] and a color correction patch [m2] are formed on the recording medium [r]. These test images are formed on the edge of the recording medium [r] outside the image forming area [A]. The position of the recording medium [r] is detected by reading the register mark [m1] formed on the downstream side of the conveying direction [F] with the reading device 11 (see FIG. 2). Furthermore, the color correction patch [m2] arranged on the upstream side of the conveying direction [F] next to the register mark [M1] is read by the reading device 11 (see FIG. 2) to perform color correction.

[0024] However, a streak-like dust [d] (e.g. dust [d']) attached near the edge of the recording medium [r] may be erroneously detected as a register mark [m1]. Such a misdetection makes it impossible to detect the color correction patch [m2] that is placed next to the register mark [m1], and makes it impossible to perform correct color correction.

[0025] Regardless of the light transmittance of the recording medium [r], such a false detection of the register mark [m1] is likely to occur when dust [d] adheres to the black background 120b. In addition, if the recording medium [r] is colored, such a false detection will also occur when dust [d] of colored paper powder adheres to the white background 120w. In particular, this false detection is likely to occur when the reading device 11 reads a test image formed on a recording medium [r] having light transmittance with white toner as an undercoat.

[0026] In addition to the above, if the recording medium [r] is light-transmitting, when dust [d] overlaps the color correction patch [m2], the color of the color correction patch [m2] may be erroneously detected. Therefore, the background device 12 has the following configuration.

[0027] Fig. 6 is a side view showing the configuration of the background device 12 of the first embodiment. Fig. 7 is a perspective view showing the configuration of the background device 12 of the first embodiment, showing a part of Fig. 6 seen from below. As shown in Figs. 6 and 7, the background device 12 includes a driving mechanism 100 for rotating the background member 12a and a cleaning unit 200 for cleaning the background member 12a. These are as follows.

[0028] [Drive mechanism 100] The driving mechanism 100 is for moving the background member 12a from a position that serves as the background of the recording medium [r]. The driving mechanism 100 has an endless belt 101, rollers 102 and 103 around which the endless belt 101 is wound, a motor 104, a pulley 105, and a timing belt 106.

[0029] The endless belt 101 has a background member 12a on its outer circumferential surface and a gear 101a on its inner circumferential side. The rollers 102 and 103 have a gear (not shown) on their outer circumferential surfaces that engages with the gear 101a of the endless belt 101. The background member 12a is configured such that a black background 120b and a white background 120w are each arranged in the rotation direction of the endless belt 101. Such a background member 12a may be, for example, a seal member bonded to the outer circumferential surface of the endless belt 101.

[0030] The motor 104 rotates the endless belt 101 to run along the conveying width direction [CD] (see FIG. 5). The pulley 105 is provided coaxially with the rotation shaft of the motor 104. A timing belt 106 is wound around the pulley 105 and a pulley portion of one of the rollers 102. As a result, the rotation of the motor 104 is transmitted to the one of the rollers 102, causing the endless belt 101 and the background member 12a arranged on the outer circumferential surface of the endless belt 101 to rotate.

[0031] Such a driving mechanism 100 is disposed so that the outer peripheral surface of the endless belt 101 between the rollers 102 and 103 faces the reading device 11 (see FIG. 2). As a result, the area between the rollers 102 and 103 becomes a reading area [A1] (see FIG. 6).

[0032] [Cleaning section 200] The cleaning unit 200 is for cleaning the background member 12a and is disposed on the opposite side of the endless belt 101 from the surface on which the reading area [A1] is set. In other words, the cleaning unit 200 is disposed opposite the background member 12a at a position to which the driving mechanism 100 has moved the background member 12a from a position that serves as the base for the recording medium [r].

[0033] The cleaning unit 200 includes a cleaning member 201 and a container 202. The cleaning member 201 is spatula-shaped and pressed against the background member 12a. The spatula-shaped tip 201a is made of, for example, a flexible rubber material. The tip 201a of the cleaning member 201 is pressed against the background member 12a in a direction perpendicular to the rotation direction of the endless belt 101. The tip 201a of the cleaning member 201 slides against the background member 12a as the background member 12a is moved by the driving mechanism 100. As a result, the position where the tip 201a is pressed against the background member 12a becomes the cleaning point of the background member 12a.

[0034] The storage box 202 has an open top and stores the cleaning member 201. The storage box 202 stores dust [d] scraped off from the background member 12a by the tip 201a of the cleaning member 201.

[0035] FIG. 8 is a side view showing the background device 12 as a modification of the first embodiment. FIG. 9 is a perspective view showing the background device 12 as a modification of the first embodiment, and is a drawing of a part of FIG. 8 seen from below. As shown in FIG. 8 and FIG. 9, the cleaning section 200' of the background device 12 may have a brush-like cleaning member 203 having a plurality of spatulas protruding from a cylindrical side peripheral wall. The spatulas of the brush-like cleaning member 203 are made of, for example, a flexible rubber material. The position where the tip of the spatula is pressed against the background member 12a is the cleaning point of the background member 12a.

[0036] The cleaning member 203 is rotatably supported by a support 204 erected on the bottom surface of the storage box 202. The cleaning member 203 has the tip of the spatula pressed against the background member 12a in a direction perpendicular to the rotation direction of the endless belt 101. This causes the cleaning member 203 to rotate in conjunction with the rotation of the background member 12a. The cleaning member 203 rotates while resisting the rotation of the background member 12a, causing the tip 201a to slide against the background member 12a. This causes the scraped dust [d] to fall into the storage box 202.

[0037] The above-described background device 12 can be retracted from the position facing the reading device 11 (see FIG. 1) by a drive unit not shown here. FIG. 10 is a diagram showing the replacement of the background member 12a and the shading member 13. As shown in state (1) of FIG. 10, the background device 12 is disposed at a position facing the reading device 11. Also, as shown in state (2) of FIG. 10, the background device 12 moves from the position facing the reading device 11 to a retracted position. In state (2), the recording medium [r] is also retracted from the position facing the reading device 11 together with the background device 12. Also, in state (2), the shading member 13 is disposed at a position facing the reading device 11. As a result, the reading device 11 reads the shading member 13.

[0038] <Shading material 13> The shading member 13 is a member that serves as a color sample during shading correction for correcting the read value by the reading device 11. During shading correction, the shading member 13 is disposed opposite the cover glass 11c of the reading device 11 as shown in state (2).

[0039] <Colorimeter 14> The colorimeter 14 measures the color of the image formed on the recording medium [r]. A background member 14a is disposed in a position facing the colorimeter 14 with the recording medium [r] interposed therebetween.

[0040] <Control unit 15> The control unit 15 includes, for example, a central processing unit (CPU), a read only memory (ROM), and a random access memory (RAM) as hardware resources of a computer. The control unit 15 centrally controls the operation of each unit of the image forming apparatus 1 by causing the CPU to read a predetermined program from the ROM, load the program into the RAM, and execute the loaded program.

[0041] The control unit 15 detects the position of the edge of the recording medium [r] based on a signal from the reading device 11, and transmits the detection result to the image forming unit 20. The control unit 15 also judges whether or not dust [d] (see Figs. 3 to 5) is attached to the background member 12a based on the signal from the reading device 11. If it is judged that dust is attached, the control unit 15 controls the driving mechanism of the background device 12 to move the background member 12a from the position that is the base of the recording medium [r], and cleans the background member 12a. The procedure for cleaning the background member 12a by the control unit 15 will be described in the next image forming method.

[0042] <Image forming method> Next, an image forming method using an image forming apparatus equipped with the inspection unit 10 described above will be described. The image forming method described here is a procedure for cleaning the background member 12a when forming an image on a recording medium [r]. This procedure is performed by an image forming program held by the control unit 15, and is carried out as follows.

[0043] First, in forming an image, the state is set to state (1) in FIG. 10, and the background device 12 is placed in a position facing the reading device 11. In this state, image formation on the recording medium [r] is started. In this case, as described with reference to FIG. 1, the long recording medium [r] unwound from the recording medium supply unit 30 is wound up in the recording medium storage unit 40, thereby transporting the recording medium [r] in the transport direction [FD]. In addition, in the image forming unit 20, an image is formed on the recording medium [r] transported in the transport direction [FD]. Furthermore, in the inspection unit 10, the image formed on the recording medium [r] is read by the reading device 11, and the color is measured by the colorimeter 14.

[0044] In the above-described image formation, the control unit 15 cleans the background member 12a as follows, based on a signal from the reading device 11. In the following, an example is shown in which an image is formed on a recording medium [r] having optical transparency, but the present embodiment is not limited to this.

[0045] [Dust adhesion detection] First, before the recording medium [r] starts to be conveyed, the reading device 11 reads a reference image of the reading area [A1] including the recording medium [r] and the background member 12a that serves as the background. The state before the recording medium [r] starts to be conveyed is the state before the image is formed on the recording medium [r], and there is no dust [d] (see FIG. 4). Therefore, the background member 12a is in a clean state.

[0046] FIG. 11 is a diagram showing a signal obtained from the reading device 11 when the background member 12a is clean. The horizontal axis indicates the reading position, and the vertical axis indicates the gradation. The background member 12a is a black background 120b on which dust [d] is easily noticeable. As shown in this figure, when the background member 12a is clean, the signal obtained from the reading device 11 has no peaks over the entire reading area [A1]. This is the same for any of the red, green, and blue signals.

[0047] The reading of the reference image is not limited to the above. During maintenance of the image forming apparatus 1, the reading device 11 may read only the background member 12a in a state where the recording medium [r] is removed from the image forming apparatus 1, and use the read image as the reference image.

[0048] After the reference image is read as described above, image formation on the recording medium [r] is started as described above. During the image formation period after the image formation is started, the reading device 11 reads the image in the reading area [A1] at a timing when the image formed on the recording medium [r] does not exist in the reading area [A1]. The image in this case also includes inspection images such as the register mark [m1] and the color correction patch [m2].

[0049] The control unit 15 periodically generates such timing during the image formation period. The reader 11 repeatedly reads the image of the reading area [A1] at this timing. If a peak occurs in the signal obtained from the reader 11 at the above timing, the control unit 15 determines that dust has adhered to the background member 12a.

[0050] Fig. 12 is a diagram showing an example of a signal obtained from a reading device during image formation. As shown in Fig. 12, when dust particles [d1] to [d4] are attached within the reading area [A1] of the background member 12a, peaks appear in the signal obtained from the reading device at the reading positions corresponding to the attachment locations of the dust particles [d1] to [d4].

[0051] It is preferable to judge whether dust has adhered to the background member 12a based on the difference between the signals in Fig. 11 and Fig. 12. When a peak occurs in the signal in this difference, the control unit 15 judges that dust has adhered to the background member 12a, thereby making a more accurate judgment. If the recording medium [r] is not optically transparent, it is judged that dust [d] has adhered to the background member 12a based on the reading result obtained within the reading area [A1] by the reading device 11 and outside the range of the recording medium [r].

[0052] It should be noted that the above-mentioned dust detection judgment is performed every 100 m when, for example, an image is formed on the recording medium [r] in a range of 0 m to 1000 m in the transport direction [FD].

[0053] [cleaning] As described above, when it is determined that the dust particles [d1] to [d4] are attached to the background member 12a, the control unit 15 cleans the background member 12a as follows.

[0054] Fig. 13 is a diagram (part 1) for explaining cleaning of the background member in the first embodiment, and is a diagram of the background device 12 seen from the side. As shown in Fig. 13, dust particles [d1] to [d4] are attached at each position between reading positions 0 mm to 400 mm within the reading area [A1] of the background member 12a. On the surface of the background member 12a, the distance of the background member 12a from the reading area [A1] to the cleaning point [P] of the cleaning unit 200 is set to 150 mm.

[0055] In this case, the control unit 15 rotates the background member 12a in a predetermined rotation direction to move the adhesion locations of the dust particles [d1] to [d4]. The control unit 15 rotates the background member 12a in such a way that the dust particle [d4] located at the reading position (350 mm) farthest from the cleaning point [P] of the cleaning unit 200 passes the cleaning point [P] with respect to the rotation direction of the background member 12a.

[0056] Fig. 14 is a diagram (part 2) for explaining cleaning of the background member in the first embodiment, and is a side view of the background device 12. As shown in Fig. 14, the control unit 15 rotates the background member 12a by a movement amount [md] obtained by adding the distance (150 mm) from the reading area [A1] to the cleaning point [P] to at least the reading position (350 mm) of the dust [d4].

[0057] As a result, all of the dust particles [d1] to [d4] attached to the background member 12a are removed from the background member 12a by the cleaning member 201. The removed dust particles [d1] to [d4] are collected in the storage box 202. The above also applies to the case where the cleaning unit 200′ described with reference to FIGS. 8 and 9 is included.

[0058] <Advantages of the First Embodiment> According to the first embodiment, the cleaning unit 200 removes the dust [d] attached to the background member 12a. This prevents the reading device 11 from reading the dust [d] attached to the background member [r] together with the image formed on the recording medium [r]. This makes it possible to prevent an error in which the dust [d] attached to the background member 12a is mistakenly recognized as the image formed by the image forming unit 20. As a result, highly accurate image formation can be achieved by control based on the read value of the test image formed by the image forming unit 20, and the downtime of the image forming apparatus 1 can be reduced.

[0059] In addition, a driving mechanism 100 is provided to move the recording medium [r] from a position that serves as the base, and a cleaning unit 200 cleans the background member 12a at the moved position. Therefore, the background member 12a can be cleaned while the long recording medium [r] is hung on the conveying mechanism of the image forming apparatus 1. This also reduces the downtime of the image forming apparatus 1 and saves the trouble of maintaining the image forming apparatus 1.

[0060] Second Embodiment Fig. 15 is a diagram for explaining the image forming method of the second embodiment, and shows two signals obtained from the reading device 11. The image forming method of the second embodiment explained using Fig. 15 differs from the image forming method of the first embodiment in the procedure of dust detection, and other procedures are similar to those of the image forming method explained in the first embodiment.

[0061] That is, the control unit 15 obtains signals from the reading device 11 before and after rotating the background member 12a. In this case, the control unit 15 rotates the background member 12a by a predetermined movement distance (for example, 100 mm) within the range of the reading area [A1].

[0062] The control unit 15 compares the first signal before rotating the background member 12a with the second signal after rotating the background member 12a. If the second signal has a similar peak at a reading position shifted by the movement distance (100 mm) from the reading position of the peak generated in the first signal, the control unit 15 determines that the peak is due to the adhesion of dust particles [d3] and [d4].

[0063] In this case, cleaning is performed in the same manner as in the first embodiment, except that the amount of rotation of the background member 12a during cleaning is set to a distance that allows the dust particles [d3] and [d4] corresponding to the peaks generated in the second signal to reach the cleaning point [P].

[0064] <Effects of the second embodiment> The second embodiment described above can achieve the same effect as the first embodiment. Furthermore, the method of the second embodiment can determine whether dust [d] has adhered to the background member 12a, regardless of the presence of an image in the reading area [A1]. If the first and second signals from the reading device 11 have similar peaks at the same position, it can be determined that these peaks are caused by dirt or scratches on the cover glass 11c of the reading device 11. In this case, the control unit 15 can notify the display unit of the image forming device 1 or a terminal device connected to the control unit 15 of dirt on the cover glass 11c and prompt the user to clean the cover glass 11c.

[0065] Third Embodiment Fig. 16 is a side view (part 1) showing the configuration of the background device 12' of the third embodiment. Fig. 17 is a side view (part 2) showing the configuration of the background device 12' of the third embodiment. In the image forming apparatus of the third embodiment, the components other than the background device 12' may be similar to the components described in the first embodiment.

[0066] 16 and 17 is disposed between two transport rollers 50 (see FIG. 2) facing the cover glass 11c of the reading device 11, similarly to the first embodiment. The background device 12' includes two rollers 12b, 12b', a driving mechanism 300 for rotating the background member 12a, and a cleaning unit 400 for cleaning the background member 12a. The two rollers 12b, 12b' and the background member 12a are similar to those described in the first embodiment, and therefore will not be described here.

[0067] [Drive mechanism 300] The driving mechanism 300 includes a roller member 301 and a motor 302 for rotating the roller member 301. The roller member 301 is disposed parallel to the transport roller 50 and the two rollers 12b, 12b'. The roller member 301 has a background member 12a provided on its outer circumferential surface. The background member 12a provided on the outer circumferential surface of the roller member 301 is a black background 120b and a white background 120w. The black background 120b and the white background 120w extend along the axial direction of the roller member 301. Such a background member 12a may be, for example, a seal member bonded to the outer circumferential surface of the roller member 301.

[0068] [Cleaning section 400] The cleaning unit 400 is for cleaning the background member 12a. The cleaning unit 400 is disposed on the opposite side to the reading device 11 with the roller member 301 interposed therebetween. The cleaning unit 400 includes a cleaning member 401, a storage box 402, and an electric actuator 403.

[0069] Among these, the cleaning member 401 is a brush-like member with a plurality of spatulas protruding from a cylindrical side wall. The spatulas of the cleaning member 401 are made of, for example, a flexible rubber material. The cylindrical cleaning member 401 is arranged parallel to the roller member 301 of the driving mechanism 300. The cleaning member 401 is supported rotatably by a support 401a erected on the bottom surface of a storage box 402, which will be described next. In addition, the tip of the cleaning member 401 slides against the background member 12a as the background member 12a is moved by the driving mechanism 300. The position where the tip of the spatula is pressed against the background member 12a is the cleaning point of the background member 12a.

[0070] The storage box 402 has an open top and stores the cleaning member 401. The storage box 402 stores dust [d] scraped off from the background member 12a by the tip of the cleaning member 401.

[0071] The electric actuator 403 is a movement mechanism for moving the cleaning member 401 along the axial direction of the roller member 301. The electric actuator 403 rotates a ball screw 403a. The ball screw 403a is fitted into the lower part of the storage box 402 and disposed in parallel with the roller member 301 of the drive mechanism 300. Driven by a motor, the ball screw 403a moves the storage box 402 and the cleaning member 401 fixed to the storage box 402 in the transport width direction [CD] along the roller member 301 of the drive mechanism 300.

[0072] The image forming method using the image forming apparatus equipped with the background device 12' as described above is carried out in the same manner as the procedure described in the first or second embodiment. However, when cleaning the background member 12a, the background member 12a is rotated by the driving mechanism 300, and the cleaning member 401 is moved by the electric actuator 403. The cleaning member 401 may be moved to the portion where dust [d] is detected.

[0073] <Effects of the third embodiment> The method of the third embodiment can obtain the same effect as that of the first embodiment. In the third embodiment, the cleaning member 401 of the cleaning unit 400 is configured to move along the roller member 301 of the drive mechanism 300. However, the cleaning member 401 and the storage box 402 may be arranged along the roller member 301 of the drive mechanism 300 within the range of the reading area [A1]. In this case, the cleaning member 401 and the storage box 402 do not need to move in the transport width direction [CD]. In this case, the cleaning member 401 may be configured to slide against the background member 12a provided on the outer circumferential surface of the roller member 301 by the rotation of the roller member 301.

[0074] Fourth Embodiment FIG. 18 is a side view showing the configuration of a background device of the fourth embodiment. In the image forming apparatus of the fourth embodiment, components other than the background device 12″ may be similar to the components described in the first embodiment.

[0075] The background device 12" shown in FIG. 18 is disposed between two transport rollers 50 (see FIG. 2) facing the cover glass 11c of the reading device 11, as in the other embodiments. The background device 12" includes a drive mechanism 500 for rotating the background member 12a and a cleaning unit 600 for cleaning the background member 12a.

[0076] [Drive mechanism 500] The driving mechanism 500 has a roller member 501. The roller member 501 is rotatable by a motor not shown here. The roller member 501 is arranged parallel to the transport roller 50. The roller member 501 is rotatable by a motor not shown here. On the outer peripheral surface of the roller member 501, the black background 120b and the white background 120w of the background member 12a are arranged along the axial direction of the roller member 501. On both sides of the black background 120b and the white background 120w, two rollers 12b and 12b' are arranged. The two rollers 12b and 12b' and the background member 12a (the black background 120b and the white background 120w) are the same as those described in the first embodiment. The background member 12a may be, for example, a seal member bonded to the outer peripheral surface of the roller member 501. However, the two rollers 12b, 12b' are supported rotatably in a state where they are fixed to the outer circumferential surface of the roller member 501.

[0077] A shading member 13 may be provided on the outer circumferential surface of the roller member 501. The shading member 13 may include, for example, a white reference member 13w and a black reference member 13b. The white reference member 13w and the black reference member 13b are arranged along the axial direction of the roller member 501. Furthermore, a cleaner 502 for cleaning the cover glass 11c of the reading device 11 may be provided on the outer circumferential surface of the roller member 501.

[0078] As described above, roller member 501 having background member 12a and rollers 12b, 12b' on its outer circumferential surface is accommodated in housing 503. Housing 503 has a large opening on the surface facing cover glass 11c of reading device 11. In addition, when shading member 13 and cleaner 502 are provided on the outer circumferential surface of roller member 501, housing 503 accommodating roller member 501 is configured to be freely accessible to cover glass 11c of reading device 11.

[0079] [Cleaning section 600] The cleaning unit 600 is for cleaning the background member 12a. The cleaning unit 600 includes a blower fan 601 fixed to the wall surface of the housing 503, a suction fan 602, and a filter 603.

[0080] The blower fan 601 blows the air [W1] onto the outer circumferential surface of the roller member 501 over the extension direction of the roller member 501. More specifically, the blower fan 601 blows the air [W1] onto the background member 12a provided on the outer circumferential surface of the roller member 501. This blows away dust [d] adhering to the background member 12a and removes it from the background member 12a. The position where the air [w1] from the blower fan 601 blows onto the outer circumferential surface of the roller member 501 is preferably a position where the outer circumferential surface of the roller member 501 faces downward.

[0081] The suction fan 602 also sucks in the air [W1] blown from the blower fan 601 onto the outer circumferential surface of the roller member 501. As a result, the suction fan 602 sucks in the dust [d] removed from the background member 12a together with the air [W1]. The suction fan 602 is disposed in a position where it can effectively suck in the air [W1] blown onto the outer circumferential surface of the roller member 501.

[0082] The filter 603 is disposed at the suction opening of the suction fan 602 and collects dust [d] contained in the blown air [W1].

[0083] The image forming method by the image forming apparatus equipped with the above-described background device 12" is carried out in the same manner as the procedure described in the first or second embodiment. However, when cleaning the background member 12a, the driving mechanism 500 rotates the background member 12a to a position corresponding to the air outlet of the blower fan 601, and the air blown by the blower fan 601 [W1] is supplied to the background member 12a.

[0084] <Effects of the Fourth Embodiment> The method of the fourth embodiment can also provide the same effects as those of the first embodiment.

[0085] In each of the above-described embodiments, the controller 15 cleans the background member 12a when it detects that dust has adhered to the background member 12a. However, the controller 15 may be configured to periodically move the background member 12a to clean the background member 12a. Furthermore, the controller 15 may be configured to move the background member 12a to clean the background member 12a when the recording medium [r] is removed during maintenance of the image forming apparatus 1. In each of the above-described embodiments, the controller 15 is configured to provide a cleaning unit for the background member 12a disposed opposite the reading device 11, but each of the embodiments is also applicable to the background member 14a of the colorimeter 14. [Explanation of symbols]

[0086] 1...Image forming device 11...Reading device 12a…Background material 12b, 12b'...Rollers (support members) 14...colorimeter 14a…Background material 15...Control section 20...Image forming section 31...Unwinder (transport mechanism) 41... Winding machine (transport mechanism) 50...Transport roller (transport mechanism) 100, 300, 500...Drive mechanism 101...Endless belt 102...Roller 104…Motor 200, 200', 400, 600...Cleaning section 201, 203, 401...Cleaning materials 201a...Tip 301, 501...Roller member 302…Motor 403...Electric actuator motor (movement mechanism) 403a...Ball screw (movement mechanism) 601...Ventilation fan 602…Suction fan [FD]…Transport direction [CD]…Transport width direction [r]…Recording medium

Claims

1. an image forming unit for forming an image on a recording medium; a reading device for reading an image forming surface of the recording medium on which the image is formed; a background member that is disposed as a base for the recording medium when the reading device reads the image forming surface of the recording medium; A cleaning unit for cleaning the background member. Image forming device.

2. a drive mechanism for moving the background member from a position that serves as a base for the recording medium; The cleaning unit is disposed opposite the background member at a position to which the background member is moved by the driving mechanism from a position serving as a base for the recording medium. The image forming apparatus according to claim 1 .

3. a conveying mechanism that conveys the recording medium in a predetermined conveying direction; a support member that supports the recording medium transported in the transport direction across a transport width direction that is substantially perpendicular to the transport direction, thereby maintaining a distance between the background member and the recording medium; The reading device reads the image forming surface of the recording medium and the background member across the transport width direction. The image forming apparatus according to claim 2 .

4. the drive mechanism includes an endless belt having the background member provided on an outer circumferential surface thereof, a roller around which the endless belt is stretched, and a motor that drives the roller to move the endless belt along the conveyance width direction; The cleaning unit is disposed opposite the reading device across the endless belt and facing the background member. The image forming apparatus according to claim 3 .

5. the cleaning unit includes a cleaning member having a tip portion pressed against an outer peripheral surface of the endless belt, The cleaning member slides against the background member as the driving mechanism moves the background member. The image forming apparatus according to claim 4 .

6. the driving mechanism includes a roller member having an outer circumferential surface on which the background member is provided and an axial direction of the roller member is the transport width direction, and a motor that rotates the roller member to rotate the background member in the circumferential direction of the roller member, The cleaning unit is disposed opposite the outer circumferential surface of the roller member on the opposite side to the reading device with respect to the roller member. The image forming apparatus according to claim 3 .

7. The cleaning unit includes: a cleaning member having a tip portion pressed against the outer circumferential surface of the roller member; a moving mechanism for moving the cleaning member along an axial direction of the roller member; 7. The image forming apparatus according to claim 6.

8. the cleaning unit includes a cleaning member having a tip portion pressed against an outer circumferential surface of the roller member, The cleaning member is slid along the background member by the rotation of the background member caused by the driving mechanism.

7. The image forming apparatus according to claim 6.

9. the driving mechanism includes a roller member having an outer circumferential surface on which the background member is provided and an axial direction of the roller member is in the transport width direction, and a motor that rotates the roller member to rotate the background member in the circumferential direction of the roller member, The cleaning unit includes a blower fan that blows air toward the background member at a position to which the background member is moved by the driving mechanism from a position that serves as a base for the recording medium. The image forming apparatus according to claim 3 .

10. The cleaning unit includes a suction fan that sucks air supplied from the blower fan to the background member. The image forming apparatus according to claim 9 .

11. A control unit for controlling the driving mechanism is provided. The control unit controls the driving mechanism to move the background member from a position that serves as a base for the recording medium. The image forming apparatus according to claim 2 .

12. When the control unit determines that the background member is soiled based on the result of reading the image by the reading device, the control unit controls the driving mechanism to move the background member from a position that serves as a base for the recording medium, and cleans the background member by the cleaning unit. The image forming apparatus according to claim 11.

13. The control unit determines whether the background member is dirty based on a result of reading the image by the reading device obtained within a range of a reading area by the reading device and outside a range of image formation on the recording medium. The image forming apparatus according to claim 12.

14. The control unit determines whether the background member is dirty based on a result of reading the image by the reading device obtained before and after the image forming unit forms an image on the recording medium. The image forming apparatus according to claim 12.

15. The control unit determines whether the background member is dirty based on the results of reading the image by the reading device obtained before and after the background member is moved by the driving mechanism. The image forming apparatus according to claim 12.

16. The control unit periodically controls the driving mechanism to move the background member from a position that serves as a base for the recording medium, and cleans the background member with the cleaning unit. The image forming apparatus according to claim 11.

17. An image forming method using an image forming apparatus including an image forming section for forming an image on a recording medium, a reading device for reading an image forming surface of the recording medium on which the image has been formed, a background member disposed as a base for the recording medium when the image forming surface of the recording medium is read by the reading device, a cleaning section for cleaning the background member, and a drive mechanism for moving the background member from a position that serves as the base for the recording medium, a control unit controls the driving mechanism to move the background member from a position that serves as a base for the recording medium; The cleaning unit cleans the background member at the moved position. Image forming method.

Images