JP3559728B2 - Image forming device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus using an electrostatic transfer process such as an electrostatic copying machine and the same printer, and includes, for example, a transfer carrier such as a transfer material carrier, and a developer image formed on the image carrier. The present invention is applied to a color image forming apparatus that obtains a color image by superimposing and transferring images on a transfer carrier.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as an image forming apparatus, many apparatuses including a step (multiple transfer) of sequentially superimposing and transferring toner images as a plurality of developer images on the same transfer material have been proposed. FIG. 9 is a side view showing an example of such an image forming apparatus.
[0003]
In such a multi-transfer image forming apparatus, when a toner image transferred to a transfer material carried on a transfer carrier in a certain image forming unit passes through a photoconductor as an image carrier of the next image forming unit, There is a disadvantage that the image is retransferred to the photoreceptor.
[0004]
In particular, when two or more colors of toner as a developer are superimposed to reproduce another color, a toner image transferred later is more sensitive than a previously transferred toner image. They tend to retransfer significantly to the body.
[0005]
In the image forming apparatus shown in FIG. 9, for example, the toner images are transferred in the color order of yellow (Y), magenta (M), cyan (C), and black (Bk) in the image forming units Pa, Pb, Pc, and Pd. In this case, it is assumed that the red (R) color is reproduced by superimposing the yellow color and the magenta color.
[0006]
Then, the magenta toner image transferred later and formed as an upper layer on the transfer material 1 carried on the transfer belt 8 as a transfer carrier is then moved under the photosensitive drums 2c and 2d as downstream photosensitive members. During the passage, the red image is re-transferred to the photosensitive drums 2c and 2d and obtained on the transfer material 1 partially or entirely has a yellowish tint.
[0007]
Similarly, when the green (G) color is reproduced by superimposing the yellow color and the cyan color, the cyan toner image as the upper layer is re-transferred to the downstream photosensitive drum 2d, and the obtained green image is A part or the whole becomes yellowish color.
[0008]
This retransfer is largely caused by abnormal discharge. Generally, among transfer papers that are most frequently used as a transfer material, a transfer paper that has absorbed moisture has a volume resistivity of 10 < ⁸ > [Omega] cm, and a dry transfer paper has a large volume resistivity of 10 < ¹³ > [Omega] cm.
[0009]
Therefore, when the toner image on the photosensitive drum 2 is sufficiently transferred to the dried transfer paper, a high transfer voltage is applied between the transfer charging unit and the photosensitive drum 2.
[0010]
Here, since there are dense and coarse portions of paper fiber inside the transfer paper, the paper fiber becomes a dielectric layer in the dense portion of paper fiber, and abnormal discharge occurs even when a high voltage is applied. Although it is difficult to do so, in the rough portion of the paper fiber (the portion where voids exist), there is an air layer which is an insulating layer, so that dielectric breakdown occurs and abnormal discharge occurs. These local abnormal discharges cause the retransfer described above.
[0011]
Conventionally, proposals have been made to cope with a change in color due to retransfer by making the color order of the transfer less noticeable or by optimizing the color reproduction parameters of an input signal and an output signal of an image. .
[0012]
Further, as another conventional technique, as described in Japanese Patent Application Laid-Open No. 9-34269, the transfer carrier is made to have a multilayer structure having a high-resistance layer and a low-resistance layer as described in JP-A-9-34269. A technique for suppressing the noise has been proposed.
[0013]
[Problems to be solved by the invention]
However, in a multi-transfer image forming apparatus using a transfer carrier having a multi-layer structure including a low-resistance layer such as a transfer material carrier such as a transfer belt or an intermediate transfer member, a multi-transfer is sequentially performed by a transfer charging unit. The surface potential of the transfer carrier gradually increases, and a high transfer voltage is applied particularly when the transfer of the fourth color is performed. Therefore, a potential difference between the transfer carrier and a member adjacent to the transfer carrier that is grounded increases. In addition, the transfer current leaks along the low resistance layer in the transfer carrier, resulting in inefficiency. In a high-humidity environment, the transfer material also has a low resistance, and thus is more susceptible to the influence.
[0014]
The present invention has been made in order to solve the above-mentioned problems of the prior art, and an object of the present invention is to obtain a high-quality image in which retransfer and the like are suppressed while transferring a transfer current from a transfer carrier to the periphery. An object of the present invention is to provide an image forming apparatus capable of suppressing the occurrence of an image.
[0015]
[Means for Solving the Problems]
In the present invention in order to achieve the above object, an image bearing member on which the developer image is formed on the surface, a transfer charging means for transferring the developer image formed on the image bearing member, said transfer charging By means, the developer is transferred to or transferred to a transfer material carrying the developer and provided in a two-layer structure in which the surface resistivity of the upper layer carrying the developer or transfer material is higher than the surface resistivity of the lower layer on the opposite side. , the surface resistivity of the lower layer is ¹⁰ 10 ~10 ¹³ Ω / □, in an image forming apparatus having a transfer carrier for traveling bridged rollers of the ground, the transfer than the previous SL transfer charging means A transfer carrier charging means for charging a lower layer of the transfer carrier to the same polarity as that of the developer is provided upstream of the carrier traveling direction and downstream of the ground roller .
[0018]
Therefore, the transfer current can easily move under the transfer carrier, and the transfer range is extended, the transfer time is lengthened, and the transfer efficiency is increased, so that the transfer can be performed with a low transfer current and the transfer carrier can be charged. Since the potential of the transfer carrier is lowered by the means, image defects such as retransfer due to abnormal discharge do not occur.
[0019]
Further, by lowering the surface potential of the transfer carrier by the transfer carrier charging means and reducing the potential difference between the transfer carrier and the adjacent member, it is possible to prevent transfer current from leaking to the adjacent member through the transfer carrier.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto unless otherwise specified. Absent.
[0021]
(First Embodiment)
The first embodiment will be described with reference to FIGS. FIG. 1 is a schematic diagram of a transfer belt as a transfer carrier according to a first embodiment of the present invention, and FIG. 2 is a schematic configuration diagram of an image forming apparatus provided with the transfer belt.
[0022]
In FIG. 2, the image forming apparatus of the present embodiment is a color multiple transfer image forming apparatus in which first, second, third, and fourth image forming units Pa, Pb, Pc, and Pd are provided. The cyan, magenta, yellow, and black toner images are sequentially formed through the processes of latent image, development, and transfer.
[0023]
Each of the image forming units Pa, Pb, Pc, and Pd includes a photosensitive member as a dedicated image carrier, in this example, electrophotographic photosensitive drums 2a, 2b, 2c, and 2d, and each of the photosensitive drums 2a, 2b, 2c, and A toner image of each color is formed on 2d.
[0024]
A transfer belt 8 as a transfer carrier is provided adjacent to each of the photosensitive drums 2a, 2b, 2c, and 2d, and a toner image of each color formed on the photosensitive drums 2a, 2b, 2c, and 2d is transferred onto the transfer belt 8. The image is transferred onto the transfer material 1 carried and transported by the.
[0025]
Further, the transfer material 1 onto which the toner images of each color have been transferred is separated from the transfer belt 8 by the separation charger 9, and is heated and pressed by the fixing unit 10 to fix the toner images. Is discharged.
[0026]
On the outer periphery of the photosensitive drums 2a, 2b, 2c, 2d, drum chargers 3a, 3b, 3c, 3d, exposure devices 4a, 4b, 4c, 4d, developing devices 5a, 5b, 5c, 5d, and transfer charging means, respectively. The transfer chargers 6a, 6b, 6c, and 6d, and the cleaners 7a, 7b, 7c, and 7d are provided, and a light source device and a polygon mirror 11 (not shown) are further provided above the apparatus.
[0027]
The developing devices 5a, 5b, 5c, and 5d are filled with a predetermined amount of cyan, magenta, yellow, and black toners, respectively, as a developer by a supply device (not shown).
[0028]
Next, the operation of the entire image forming apparatus will be described. First, the laser light emitted from the light source device is rotated and scanned by the polygon mirror 11, the light beam of the scanning light is deflected by the reflection mirror, and collected on the generatrix of the photosensitive drums 2a, 2b, 2c and 2d by the fθ lens. By performing light exposure, a latent image corresponding to an image signal is formed on the photosensitive drums 2a, 2b, 2c, and 2d.
[0029]
The developing devices 5a, 5b, 5c, and 5d develop the latent images on the photosensitive drums 2a, 2b, 2c, and 2d, respectively, and visualize the latent images as cyan, magenta, yellow, and black toner images. I do.
[0030]
On the other hand, the transfer material 1 is accommodated in a transfer material cassette 30 and is supplied from there to a transfer belt 8 via a plurality of transfer rollers and registration rollers 13. The transfer by the transfer belt 8 causes the photosensitive drums 2 a, 2 b, 2 c and 2 d to be transferred. Are sequentially sent to the transfer section opposite to.
[0031]
As the transfer belt 8, an endless shape belt or a seamless (seamless) belt is used.
[0032]
Then, the transfer belt 8 is rotated in a direction indicated by an arrow X by a drive roller 14, the transfer material 1 is sent out from the registration roller 13 to the transfer belt 8, and the transfer material 1 is directed toward the transfer portion of the first image forming unit Pa. Conveyed.
[0033]
At the same time, the image writing signal is turned on, and an image is formed on the photosensitive drum 2a of the first image forming unit Pa at a certain timing based on the signal.
[0034]
Then, the transfer charger 6a applies an electric field or electric charge at the lower transfer portion of the photosensitive drum 2a, so that the first color toner image formed on the photosensitive drum 2a is transferred onto the transfer material 1.
[0035]
By this transfer, the transfer material 1 is firmly held on the transfer belt 8 by electrostatic attraction, and is conveyed to the second image forming portion Pb and thereafter.
[0036]
Here, as the transfer chargers 6a, 6b, 6c, 6d, contact chargers using a transfer charging member such as a blade, a roller, or a brush are used. The contact charger has advantages such as ozonelessness, resistance to temperature and humidity environment fluctuation, and high image quality.
[0037]
Further, image formation and transfer in the second to fourth image forming units Pb to Pd are performed in the same manner as in the first image forming unit Pa.
[0038]
Next, the transfer material 1 to which the four color toner images have been transferred is discharged from the end of the transfer belt 8 by removing electricity by the separation charger 9 to attenuate the electrostatic attraction force on the downstream side in the transport direction of the transfer belt 8. break away.
[0039]
In particular, in a low-humidity environment, the transfer material 1 also dries and the electric resistance increases, so that the electrostatic attraction force with the transfer belt 8 increases, and the effect of the separation charger 9 increases.
[0040]
Normally, the separation charger 9 charges the transfer material 1 in a state where the toner image is not fixed, and thus a non-contact charger is used.
[0041]
Further, a charge removing roller 16 is provided to face the driving roller 14, and the transfer belt 8 from which the transfer material 1 has been separated is subjected to charge removal by the charge removing roller 16.
[0042]
Then, the transfer material 1 detached from the transfer belt 8 is conveyed to the fixing device 10, where the color mixture of the toner image and the fixation to the transfer material 1 are performed by fixing, and a full-color copy image is formed. Is discharged.
[0043]
Next, the transfer belt 8 which is a feature of the present invention will be described. As shown in FIG. 1, the transfer belt 8 includes two layers, an upper layer 41 and a lower layer 42. In this embodiment, the upper layer 41 has a surface resistivity of 10 ¹⁴ Ω / □, the lower layer 42 has a surface resistivity of 10 ¹¹ Ω / □, the volume resistivity of the entire transfer belt 8 is 10 ¹⁴ Ωcm, and the thickness thereof is 80 μm. A polyimide endless belt was used.
[0044]
Here, the resistance adjustment of the upper layer 41 and the lower layer 42 of the transfer belt 8 is performed by changing the addition amount of the upper layer 41 and the lower layer 42 when carbon as a conductive material is added to the polyimide of the base layer.
[0045]
In selecting the resistance value of the transfer belt 8, if the surface resistivity ρs of the transfer belt 8 is too low, the electric field applied at the time of transfer depends on the surrounding potential state in order to obtain a good transfer image with the transfer belt 8. , And the electric field leaks to the surroundings, resulting in inefficiency.
[0046]
Then, the amount of the transfer electric field contributing to the transfer differs between the case where the transfer electric field leaks from the transfer chargers 6a, 6b, 6c and 6d and the case where it does not. A level difference occurs.
[0047]
On the other hand, when the surface resistivity ρs of the transfer belt 8 is high, the charge decay amount decreases. Accordingly, for example, in FIG. 2, when the transfer charging is repeatedly performed on the transfer belt 8 from the first image forming unit Pa to the fourth image forming unit Pd, the transfer belt 8 is finally transferred to the fourth image forming unit Pd. 8 requires a large amount of power for charging. If constant current control is performed at the time of transfer, a larger high voltage is required if the surface resistivity ρs is large.
[0048]
Then, not only power consumption and apparatus cost, but also a discharge phenomenon at the time of transfer is likely to occur, and a good transfer image cannot be obtained, and the latitude of the optimum applied electric field is reduced.
[0049]
In the image forming apparatus of the present embodiment, if the surface resistivity of the lower layer, which is the charging side of the transfer belt, is set to 10 ⁹ Ω / □ or less, a density step occurs due to transfer electric field leakage, and the surface resistivity of the lower layer becomes 10 ^14. When the value was Ω / □ or more, occurrence of image defect due to abnormal discharge during transfer was observed.
[0050]
FIG. 3 is a diagram showing the vicinity of the transfer charger 6a of the first image forming unit Pa. A transfer current flows from the transfer charger 6a, and the toner image formed on the photosensitive drum 2a is transferred onto the transfer material 1.
[0051]
At this time, since the surface resistivity of the lower layer 42 provided on the side of the transfer charger 6a of the transfer belt 8 is low, the transfer current easily moves on the surface of the transfer belt 8, so that the transfer nip where the transfer is performed is widened. Since the transfer time is longer, the transfer efficiency is improved.
[0052]
Therefore, the transfer can be favorably performed with a lower transfer current. Therefore, only a low transfer voltage needs to be applied, and image defects such as retransfer due to abnormal discharge are less likely to occur. Further, since the volume resistivity of the entire transfer belt 8 is high, the scattering of the toner image transferred onto the transfer material 1 due to the charge amount attenuation is reduced.
[0053]
In the image forming apparatus according to the present embodiment, when the volume resistivity of the transfer belt is 10 ¹² Ωcm or less, an image defect due to scattering occurs. In the case of a transfer belt having a thickness of 150 μm or more, the capacitance was small, and an image defect due to abnormal discharge occurred.
[0054]
FIG. 4 is a diagram illustrating transfer voltages applied to the first to fourth image forming units Pa, Pb, Pc, and Pd. Graph 61 is for a polyimide single-layer belt with a volume resistivity of 10 ¹⁴ Ωcm and surface resistivity of 10 ¹⁴ Ω / □ on both sides, and graph 62 is for the transfer belt 8 of the present embodiment used this time. The upper layer 41 has a surface resistivity of 10 ¹⁴ Ω / □, the lower layer 42 has a surface resistivity of 10 ¹¹ Ω / □, and the volume resistivity of the entire transfer belt 8 is a 10 ¹⁴ Ωcm polyimide two-layer belt.
[0055]
As shown in FIG. 4, the transfer voltage applied to the transfer belt 8 may be low, and the above effect can be recognized.
[0056]
On the other hand, a transfer belt charging means 21 as a transfer carrier charging means for charging the surface opposite to the toner image bearing surface of the transfer belt 8, that is, the back surface, to the same polarity as the toner upstream of the transfer charger 6 a in the running direction of the transfer belt 8. It has.
[0057]
As shown in FIG. 5, the transfer belt charging means 21 has conductive rollers 51 and 52 disposed so as to sandwich the transfer belt 8, and a conductive roller provided on a surface of the transfer belt opposite to the toner image bearing surface. A negative DC bias is applied to 51 from a high voltage power supply 53. Further, the toner image bearing surface of the transfer belt 8 opposite thereto, that is, the conductive roller 52 provided on the surface is grounded.
[0058]
FIG. 6 is a graph showing the potential of the transfer belt 8 when passing through the first to fourth image forming units Pa, Pb, Pc, and Pd in the image forming apparatus of FIG. Graph 71 shows the case where the transfer belt charging unit 21 was not used, and graph 72 shows the case where a DC bias of −2 kV was applied by the transfer belt charging unit 21 with respect to the transfer belt 8 having two layers of polyimide used this time. belongs to.
[0059]
As the toner images are sequentially transferred in the first to fourth image forming units Pa, Pb, Pc, and Pd, a higher transfer voltage is required toward the subsequent image forming units. When the potential is removed by the roller 16 and the potential on the transfer charger 6a side of the transfer belt 8 immediately before the first image forming unit Pa is set to 0 kV, the transfer charger 6d is considerably higher in the fourth image forming unit Pd. A transfer voltage is applied.
[0060]
In this case, for example, a potential difference from an adjacent member such as the grounded drive roller 14 becomes large, and a transfer current flows into the drive roller 14 side, resulting in a problem that the transfer current is insufficient and the image density is reduced.
[0061]
On the other hand, when a negative voltage is applied to the transfer charger 6a side of the transfer belt 8 by the transfer belt charging means 21 and the potential is set to be negative, the potential of the transfer belt 8 also becomes the fourth image forming portion Pd. As a result, the potential difference between the transfer belt 8 and the member adjacent to the transfer belt does not increase, so that the transfer current does not flow into the member adjacent to the transfer belt, and a good image can be obtained.
[0062]
FIG. 7 is a diagram illustrating transfer voltages applied to the first to fourth image forming units Pa, Pb, Pc, and Pd. The graph 81 shows the case where the transfer belt charging unit 21 was not used, and the graph 82 shows the case where a DC bias of −2 kV was applied by the transfer belt charging unit 21 with respect to the polyimide two-layer transfer belt 8 used now.
[0063]
As shown in FIG. 7, the present embodiment uses the transfer belt 8 and further uses the transfer belt charging unit 21, so that the transfer voltage applied in the fourth image forming unit Pd is further reduced. Image defects such as retransfer due to abnormal discharge can be further suppressed. In addition, since the surface resistivity of the transfer belt 8 on the side where the transfer belt charging means 21 is provided is low, the nip for charging is widened as in the case of the transfer chargers 6a, 6b, 6c and 6d, and the efficiency is improved. Thus, the transfer belt 8 can be reversely charged.
[0064]
As described above, the structure of the transfer belt 8 is made up of two layers having different surface resistivity, the resistance value is optimized, and the surface potential of the transfer belt 8 is lowered by the transfer belt charging means 21 so that the transfer belt 8 can perform retransfer due to abnormal discharge. Image defects can be suppressed.
[0065]
In addition, the transfer belt charging means 21 lowers the surface potential of the transfer belt 8 and reduces the potential difference between the transfer belt 8 and a member adjacent to the transfer belt, so that the transfer current leaks through the low-resistance layer in the transfer belt 8. Can be prevented.
[0066]
In the transfer belt 8 of the present embodiment, the upper layer 41 has a surface resistivity of 10 ¹⁴ Ω / □ and the lower layer 42 has a surface resistivity of 10 ¹¹ Ω / □, but the lower layer has a surface resistivity of 10 ¹⁰ to 10 ^13. The above effect can be better achieved if Ω / □ and the surface resistivity of the upper layer are 10 ¹³ Ω / □ or higher, which are higher than those of the lower layer.
[0067]
The transfer belt 8 of the present embodiment has a volume resistivity of 10 ¹⁴ Ωcm and a thickness of 80 μm of the entire transfer belt 8. However, the transfer belt 8 has a volume resistivity of 10 ¹³ Ωcm or more and a thickness of 150 μm or less. This is a preferred mode in which the above-mentioned effects can be achieved.
[0068]
(Second embodiment)
Next, a second embodiment will be described with reference to FIG. This embodiment is different from the first embodiment in that the two-layer belt of the present invention is used for an intermediate transfer belt, which is an intermediate transfer member, instead of a transfer belt that carries a transfer material.
[0069]
Other configurations and operations are the same as those of the first embodiment, and therefore, the same components will be denoted by the same reference characters and description thereof will be omitted.
[0070]
In FIG. 8, the photosensitive drums 2a, 2b, 2c, and 2d are provided. However, as a first transfer carrier, an intermediate transfer belt (primary transfer belt) 8a for the photosensitive drums 2a, 2b, 2c, and 2d is used. In addition, a transfer belt (secondary transfer belt) 8b for supporting a transfer material as a second transfer carrier, and a transfer carrier of the present invention similar to that of FIG. 1 is used for the primary transfer belt 8a. .
[0071]
The toner images of the respective colors of the photoconductors 2a to 2d are temporarily superimposedly transferred onto the primary transfer belt 8a, and then the transferred toner images are collectively transferred to the transfer material 1 on the secondary transfer belt 8b. ing. Further, a transfer belt charging unit 21 is provided upstream of the first image forming unit Pa in the traveling direction of the primary transfer belt 8a.
[0072]
In the image forming apparatus having the above configuration, similarly to the first embodiment, image defects such as retransfer due to abnormal discharge do not occur, and image defects due to a transfer current flowing to a member adjacent to the primary transfer belt 8a. Also did not occur.
[0073]
Also, a good image can be obtained by using the transfer carrier as shown in FIG. 1 for the secondary transfer belt 8b.
[0074]
【The invention's effect】
As described above, according to the present invention, the transfer carrier is provided in a two-layer structure in which the surface resistivity of the upper layer supporting the developer image or the transfer material is higher than the surface resistivity of the lower layer on the opposite side. A transfer carrier charging means for charging the lower layer of the transfer carrier to the same polarity as the developer is provided upstream of the transfer carrier in the traveling direction of the transfer carrier, so that the transfer current can easily move through the lower layer of the transfer carrier. Since the transfer range is extended, the transfer time is lengthened and the transfer efficiency is increased, so that the transfer can be performed with a low transfer current, and the potential of the transfer carrier is lowered by the transfer carrier charging means. The image defect such as the above does not occur, and a high quality image can be obtained.
[0075]
Further, by lowering the surface potential of the transfer carrier by the transfer carrier charging means and reducing the potential difference between the transfer carrier and the adjacent member, it is possible to prevent the transfer current from flowing through the transfer carrier into the adjacent member.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a transfer belt according to a first embodiment.
FIG. 2 is a schematic configuration diagram illustrating an image forming apparatus according to the first embodiment.
FIG. 3 is a diagram illustrating the vicinity of a transfer charger in a first image forming unit.
FIG. 4 is a diagram illustrating transfer voltages applied to first to fourth image forming units when a single-layer belt and the two-layer belt of the present invention are used.
FIG. 5 is a configuration diagram showing a transfer carrier charging unit.
FIG. 6 is a graph showing the potential of the transfer belt when passing through the first to fourth image forming units.
FIG. 7 is a diagram illustrating transfer voltages applied to first to fourth image forming units depending on whether or not charging is performed by a transfer carrier charging unit.
FIG. 8 is a schematic configuration diagram illustrating an image forming apparatus according to a second embodiment.
FIG. 9 is a schematic configuration diagram illustrating a conventional image forming apparatus.
[Explanation of symbols]
1 Transfer Materials 2a, 2b, 2c, 2d Photosensitive Drums 3a, 3b, 3c, 3d Drum Chargers 4a, 4b, 4c, 4d Exposure Devices 5a, 5b, 5c, 5d Developing Devices 6a, 6b, 6c, 6d Transfer Chargers 7a, 7b, 7c, 7d Cleaner 8 Transfer belt 8a First transfer belt 8b Second transfer belt 21 Transfer belt charging means 41 Upper layer 42 Lower layer 51, 52 Conductive roller 53 DC bias power supply

Claims (1)

An image carrier on which a developer image is formed,
Transfer charging means for transferring the developer image formed on the image carrier ,
By said transfer charging means it is transferred to a transfer material to which the developer is or supported is transferred, the developer or the transfer material 2 layer higher than the layer of surface resistivity opposite lower surface resistivity of carrying the A transfer carrier that is provided in a structure, has a surface resistivity of the lower layer of 10 ¹⁰ to 10 ¹³ Ω / square, and runs across a grounded roller ;
In the image forming apparatus having
On a downstream side of the transfer carrier traveling direction upstream and rollers of the ground than the previous SL transfer charge means, characterized in that a transfer bearing member charging means for charging the lower layer of the transfer carrier to the developer the same polarity Image forming apparatus.

Images