JP4595625B2 - Developing roller sorting method - Google Patents

Description

The present invention relates to a developing roller used in a developing method in an electrophotographic image forming apparatus, and more particularly to a developing roller selection method for obtaining a developing method excellent in toner transportability.

  Conventionally, in an electronic image forming apparatus, a toner of developer is supplied to a developing roller, and a thin layer of toner is formed on the developing roller and a bias voltage is applied to the developing roller by a regulating member. There is known a developing method using a non-magnetic one-component toner in which a latent image is transferred to an electrostatic latent image formed on an electrostatic latent image holding member and a toner image is made visible in the electrostatic latent image.

  In a developing roller used in such an electronic image forming apparatus, a technique for processing a roller surface using a polishing machine such as a rubber roller mirror finishing machine has been conventionally known in order to increase a toner conveyance amount. The difference in the surface state (polishing state) of the developing roller has had a great influence on the printed image.

The surface roughness of the developing roller is set to 10 to 60 μm on the surface of the conductive rubber roller having a surface roughness of Rz (ten point average roughness) of 1.0 to 15 μm. In view of this, there has been proposed a developing roller that can be maintained in a suitable state and has a long service life despite its thin outer layer thickness. (For example, refer to Patent Document 1.)
Japanese Patent Laid-Open No. 7-084443 ("Summary", Fig. 1)

  By the way, it is considered that the surface roughness of the developing roller may be increased in order to impart sufficient toner transportability to the developing roller. Therefore, as described above, there is Rz as a standard indicating the surface roughness of physical properties. However, as in the technique of Patent Document 1 above, the surface roughness of the developing roller is defined only by Rz, and this developing roller is not in contact with the developing roller. Experiments with solid image printing in a type of electrophotographic system in which toner of one magnetic component is conveyed revealed that the toner could not be sufficiently conveyed.

  In other words, in the experiment, there was a problem of “solid followability failure” in which the solid density of the solid printed image after the first round of the developing roller was lowered, resulting in a problem of lowering the image quality. Therefore, in order to define the appropriate roughness of the developing roller surface, the physical property parameter cannot be properly managed only by Rz.

An object of the present invention is to provide a developing roller selection method for obtaining a developing method excellent in toner transportability in an electrophotographic image forming apparatus in view of the above-described conventional situation.

Hereinafter, describing the structure of the sorting how the developing roller according to the present invention.
The developing roller sorting method of the present invention is based on a polishing process and is selected from rubber-like rollers having irregularities formed on the surface, and the electrostatic latent image held on the latent image carrier is treated with a non-magnetic one-component toner. This is a developing roller selection method used in the developing method for visualizing, wherein the peripheral surface is observed with a laser microscope, the area of the measurement plane of the peripheral surface is S0, and the surface area of the uneven portion in the measurement plane region is S. when a configured sorting roller S / S0 is 2.37 or more.

The toner carrier, for example, made of NBR (acrylonitrile butadiene rubber).

According to the present invention, the selection method of the developing roller used in the developing method using a non-magnetic one-component toner in an electrophotographic image forming apparatus, in the rubbery roller uneven surface based on the polishing is formed S / S0 is 2.37 or more, when the peripheral surface of the roller is observed using a laser microscope, the area of the measurement plane of the peripheral surface is S0, and the surface area of the irregularities in the measurement plane region is S. Since the configuration is such that a certain roller is selected, it is possible to provide a developing method and a developing device with good toner transportability regardless of the physical property parameter Rz.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 is a cross-sectional view illustrating an internal configuration of a color image forming apparatus (hereinafter simply referred to as a printer) in Embodiment 1 of the present invention. As shown in FIG. 1, the printer 1 includes an image forming unit 2, a duplex printing transport unit 3, and a paper feeding unit 4. The image forming unit 2 has a configuration in which four image forming units 5 (5-1, 5-2, 5-3, 5-4) are arranged in a multistage manner.

  Of the four image forming units 5, the three image forming units 5-1, 5-2, and 5-3 on the upstream side in the sheet conveying direction are magenta (M) and cyan (C ), A monochrome image is formed with yellow (Y) color toner, and the image forming unit 5-4 forms a monochrome image mainly with black (K) toner such as characters.

  Each of the image forming units 5 includes a drum unit DU and a toner unit TU, and has the same configuration except for the developer (color) stored in the developing container. Therefore, the configuration of the yellow (Y) image forming unit 5-3 will be described below as an example.

  The drum unit DU is provided with a photosensitive drum 6, and a cleaner 7 and a charging roller 8 that surround the vicinity of the peripheral surface of the photosensitive drum 6 and constitute the drum unit DU together with the photosensitive drum 6 are arranged. . Further, a print head 9 supported by a frame of the main body device is disposed in the vicinity of the upper peripheral surface of the photosensitive drum 6, and is in contact with the lower peripheral surface of the photosensitive drum 6 so as to sandwich the transport belt 10. The transfer device 11 is arranged.

  The toner unit TU is a developing device, and a developing container 12 and a developing roller 13 are disposed. The developing container 12 contains toner therein and supports the developing roller 13 in the opening on the lower side surface. In order to prevent toner aggregation, aluminum oxide fine particles are added to the toner as an external additive. Aluminum oxide has a weaker negative potential than the weak negative potential of the toner, and is relatively positive with respect to the toner and adheres to the toner.

  The photosensitive drum 6 rotates in the clockwise direction in the figure, the peripheral surface is cleaned by the cleaner 7, and the peripheral surface of the photosensitive drum 6 is uniformly charged by the charge application from the charging roller 8. Next, an electrostatic latent image is formed on the peripheral surface of the photosensitive drum 6 by optical writing based on the print information from the print head 9. The electrostatic latent image is converted into a toner image by yellow (Y) toner stored in the developing container 12 by the developing process by the developing roller 13.

  The toner image formed on the peripheral surface of the photosensitive drum 6 in this way reaches the transfer portion where the photosensitive drum 6 and the transfer device 11 face each other as the photosensitive drum 6 rotates. The toner image that has reached the transfer portion is transferred onto a sheet that moves from the upstream side to the downstream side in the sheet conveyance direction immediately below the photosensitive drum 6.

  The sheet is carried out of the sheet feeding cassette 15 by one rotation of the sheet feeding roller 14, and is fed to the standby roller pair 19 through the guide roller pair 16, the guide path 17, and the feeding roller pair 18. Alternatively, the paper is fed by the paper feed roller 22 from the MPF tray 21 mounted on the opened mounting portion cover 20.

  The standby roller pair 19 feeds the sheet onto the conveying belt 10 at a timing when the sheet printing start position coincides with the leading edge of the toner image on the photosensitive drum 6 of the image forming unit 5-1 at the most upstream in the sheet conveying direction.

  The conveyor belt 10 is stretched between a driving roller 23 and a driven roller 24, driven by the driving roller 23, and circulated in the counterclockwise direction in the figure. The sheet is electrostatically adsorbed and conveyed on the upper surface of the circulating and conveying belt 10, and a magenta (M) toner image is transferred by the transfer unit of the image forming unit 5-1, and the image forming unit 5-2. The cyan (C) toner image is transferred at the transfer portion, the yellow (Y) toner image is transferred at the transfer portion of the image forming unit 5-3, and the black ( The toner image of K) is transferred.

  The paper onto which the four color toner images are transferred in this manner is carried into a fixing unit 25 which is a fixing device. The fixing unit 25 is composed of a heat roller 26, a pressure roller 27, an oil application roller 28, and the like. While the paper is nipped and conveyed between the heat roller 26 and the pressure roller 27, the toner image is melted and pressed onto the paper surface. And fix. The oil application roller 28 has a function of applying toner releasing oil to the peripheral surface of the heat roller 26 and removing toner remaining on the heat roller 26.

  As described above, the sheet on which the toner image is fixed by the fixing unit 25 forms an image from the side discharge port 32 by the carry-out roller pair 31 when the switching plate 29 is rotated upward as shown by the solid line in the figure. When the switching plate 29 is rotated downward as indicated by the broken line in the figure, it is guided upward by the conveying roller pair 33 and the sheet discharge roller 34 moves the image forming surface. The paper is discharged downward to the paper discharge unit 35.

  The double-sided printing transport unit 3 is configured to be detachable from the apparatus main body, and is a unit that is mounted when performing double-sided printing by the printer 1 of this example, and a plurality of transport rollers 36a to 36e are disposed therein. Has been.

  In the case of duplex printing, the paper is once sent upward by the switching plate 29. For example, when the trailing edge of the paper reaches the conveyance roller pair 33, the conveyance of the paper is stopped and the paper is further conveyed in the reverse direction. . By this control, the sheet is conveyed downward on the left side of the switching plate 29 set at the position indicated by the dotted line, is carried into the sheet conveyance path of the duplex printing conveyance unit 3, and is conveyed by the conveyance rollers 36a to 36e. It reaches the standby roller pair 19 via the guide path 17 and the feed roller pair 18 and is sent to the transfer unit at the same timing as the toner image as described above, and the toner image is transferred to the back surface of the paper.

  The density sensor 37 provided in the vicinity of the drive roller 23 is composed of, for example, a near-infrared regular reflection type sensor, and is composed of a light-emitting unit formed by LEDs and a light-receiving unit including a light-receiving element that detects the amount of LED light. ing.

  The density sensor 37 is directly formed on the end of the peripheral surface of the conveyor belt 10 for measuring the toner density and the print position of a toner image directly formed on the central portion of the peripheral surface of the conveyor belt 10 as a resist patch. It is arranged for measuring a white band check patch of a toner image.

  FIG. 2 is an external perspective view of the printer 1. As shown in the figure, the printer 1 is composed of an apparatus main body upper part 38 and an apparatus main body lower part 39. An operation panel 41 is disposed in front of the upper surface of the apparatus main body upper part 38, and also shown in FIG. A printing paper discharge section 35 is formed. The operation panel 41 includes a key operation unit 41a provided with a plurality of keys and a display unit 41b such as a liquid crystal display. In addition, printing paper on which toner images are fixed is output and sequentially stacked on the paper discharge unit 35 by the rotation of the paper discharge roller pair 34 shown in FIG.

  Further, a front cover 42 that can be opened and closed in the arrow direction c is provided at the apparatus main body lower portion 39. The front cover 42 is opened at the time of jam processing or maintenance, for example.

  FIG. 3 is a block diagram showing a circuit configuration of the control device of the printer 1. As shown in the figure, the control device 43 includes an interface controller (shown simply as an I / F in the figure) 44 and a printer controller 45 (PR_CONT) connected to the interface controller 44. A host computer (not shown) is connected to the interface controller 44, and data (print information) is input from the host computer.

  A printer printing unit 46 is connected to the printer controller 45. A central processing unit (CPU) 47 is connected to the interface controller 44 and the printer controller 45, and the CPU 47 controls the interface controller 44 and the printer controller 45 according to a system program stored in a ROM (read only memory) 48.

  The interface controller 44 creates pattern data corresponding to one page of printing paper according to the printing information output from the host computer. At this time, the pattern data created by the interface controller roller 44 is, for example, data corresponding to each color of yellow (Y), magenta (M), cyan (C), and black (K). The data is stored in the storage areas 49M, 49C, 49Y, and 49K for each color of the frame memory 49 disposed in the interface controller roller 44. The pattern data is output to the printer controller 45 under the control of the CPU 47, and is output to the printer printing unit 46 for each color of magenta (M), cyan (C), yellow (Y), and black (K).

  The operation panel 41 is connected to the CPU 47 and outputs various operation signals from the outside to the CPU 47. An EEPROM (electrically erasable programable ROM) 51 stores, for example, a paper size detected by a paper feed sensor (not shown).

  Next, the basic operation of the printer 1 having the above configuration will be described with reference to FIGS. First, power is turned on to the main unit 1, and printing (printing) is started when the number of sheets to be used, the print mode, and other designations are input as a key input or a signal from a connected host device.

  That is, the sheet feeding roller 14 shown in FIG. 1 is rotated once by a driving mechanism (not shown), and the sheet placed and accommodated in the sheet feeding cassette 15 is passed through the guide roller pair 16, the guide path 17, and the feeding roller pair 18. To the standby roller pair 19.

The standby roller pair 19 temporarily stops the rotation, and waits for the conveyance timing in a state where the leading end of the sheet is brought into contact with the holding portion formed by the pair of rollers.
Subsequently, the drive roller 23 rotates in the counterclockwise direction, and the driven roller 24 is driven to rotate in the same counterclockwise direction. As a result, the transport belt 10 is circulated and moved in the counterclockwise direction as a whole by the upper circulation portion coming into contact with the four photosensitive drums 6.

  At the same time, each drum unit DU and toner unit TU are sequentially driven in accordance with the printing timing. The photosensitive drum 6 rotates clockwise, the charging roller 8 applies a uniform high negative charge to the circumferential surface of the photosensitive drum 6, and the print head 9 generates an image signal on the circumferential surface of the photosensitive drum 6. Accordingly, exposure is performed to form a low potential portion. As a result, an electrostatic latent image composed of a high negative potential portion by the charging roller 8 and a low negative potential portion by exposure is formed. The developing roller 13 of the toner unit TU transfers the toner to the low potential portion of the electrostatic latent image to form a toner image (reverse development) on the circumferential surface of the photosensitive drum 6.

  At the timing when the leading edge of the toner image on the circumferential surface of the photosensitive drum 6 located at the uppermost stream is rotated and conveyed to a point facing the conveying belt 10, the printing start position of the sheet coincides with the opposite point. The standby roller pair 19 starts rotating and feeds the paper to the paper carry-in section. The sheet is adsorbed by the conveyance belt 10 and conveyed to the first transfer unit formed by the photosensitive drum 6 and the transfer unit 11 of the image forming unit 5-1.

  The transfer unit 11 applies a transfer current output from the transfer bias power source to the sheet via the conveyance belt 10. The M (magenta) toner image on the photosensitive drum 6 is transferred onto the sheet by the transfer current applied from the transfer unit 11. Subsequently, the C (cyan) toner image is transferred at the transfer portion of the second image forming unit 5-2 from the upstream, and the Y (yellow) toner is transferred at the transfer portion of the third image forming unit 5-3 from the upstream. The toner image is transferred. Then, K (black) toner images are sequentially transferred in the transfer section of the image forming unit 5-4 that is fourth from the upstream (that is, the most downstream).

  In this way, the sheet on which the four color toner images are transferred is separated from the conveyor belt 10 and carried into the fixing unit 25. The fixing unit 25 fixes the toner image on the sheet with heat and pressure. After the image is fixed, the sheet is discharged onto the upper discharge section 35 by, for example, the transport roller pair 33 and the discharge roller pair 34 with the toner image facing down.

  FIG. 4 is a side sectional view showing the configuration of the main part of the image forming unit 5 in detail. As shown in FIG. 1, the image forming unit 5 shown in the figure is detachable from the printer 1 and is composed of a drum unit DU and a toner unit TU.

  The toner unit TU includes a developing container 12 that also serves as a toner hopper, and a developing roller 13 formed of a conductive rubber roller having irregularities on the surface thereof is rotatably held in a lower opening of the developing container 12. Inside the developing container 12, a toner 52 is accommodated, and an agitating member 53 that agitates the toner is provided so as to be buried in the toner 52.

  In addition, a supply roller 54 made of a sponge body is disposed in pressure contact with the developing roller 113 at the bottom of the developing container 12. The developing roller 13 is provided with a metal leaf spring doctor blade 55 in pressure contact with the oblique upper right peripheral surface thereof, and a squeeze sheet (conductive regulation sheet) 56 is provided in contact with the lower peripheral surface. Yes. The squeeze sheet 56 is provided with a squeeze sheet bias power source 57 for supplying a bias voltage to the squeeze sheet 56. A developing roller bias power source 59 is connected to the developing roller.

  Further, on both sides of the doctor blade 55, sealing members 58 for separating the inside and the outside of the opening of the developing container 12 and preventing leakage of the toner 52 are disposed. A common toner bias power supply 61 is connected to the doctor blade 55 and the supply roller 54.

  As described above, the developing container 12 employs a contact developing (roller) system in which the developing roller 13 composed of a conductive rubber roller having an uneven surface is pressed against the surface of the photosensitive drum 6. With the above-described apparatus configuration, high-speed and high-quality development using a non-magnetic one-component toner system is obtained.

  By the way, in order to give unevenness to the surface of the developing roller 13 as described above, surface polishing by a polishing machine is performed. Examples of the polishing machine include a CG50 type cylindrical grinding machine manufactured by Miyamoto Seisakusho as a normal polishing machine, and an SP100 type film polishing machine manufactured by Matsuda Seiki as a film polishing machine.

  As described above, in order to impart sufficient toner transportability to the developing roller, the physical property parameter of the surface roughness of the developing roller is inappropriate for Rz, and it is necessary to set other physical property parameters.

  This seems to be impossible with a normal polishing machine, and it was considered that a finisher process using a film polishing machine used as a rubber roller mirror finisher was necessary. In addition, a film grinder is a grinder which grind | polishes, winding up the roll film which apply | coated the abrasive grain.

  In this example, an inexpensive NBR is used as a rubber material as a material of the developing roller 13. The electric resistance of the developing roller is 2000 to 15000 kΩ (4.9 N load on both ends of the roller, and the measurement voltage is 500 V). And the surface grinding | polishing was performed using the rubber roller mirror surface finishing machine as the surface processing.

  As the polishing machine, a polishing machine manufactured by SP100 type Matsuda Seiki Co., Ltd. was used, and as the polishing tape, Sankyo Rika Chemical film numbers of # 400, # 600, and # 800 were used. Then, prototype developing rollers 13n (n = 1, 2, 3,...) Having various surface roughnesses (unevenness) are created by changing the count of the polishing tape, and these evaluation tests are performed to obtain the following The result was obtained.

FIG. 5 is a table showing the results of an evaluation test of toner followability after surface polishing by a rubber roller mirror finisher of the developing roller.
In the column of the sample shown in the figure, the prototype developing roller 13n that was evaluated as good as a result is shown as Examples 1 to 8, and the prototype developing roller 13n that was evaluated as a result is shown as Comparative Examples 1 to 14.

Further, the S / S0 column shows a specific area ratio S / S0 obtained by measuring the polishing state of the developing roller surface after the surface polishing by the rubber roller mirror finisher with a laser microscope.
In the measurement of the developing roller surface, a laser microscope VK-8550 manufactured by Keyence Corporation was used. A 50 × objective lens was used for the laser microscope. The field of view of the laser microscope was set to 1000 times.

  “S0” in the above-mentioned area ratio S / S0 indicates the area of the measurement region by the laser microscope, that is, the area of the measurement plane. In this example, the measurement plane area S0 is set to 298.3 μm × 223.7 μm. In addition, “S” in the area ratio S / S0 indicates the surface area of the uneven portion obtained by measurement with a laser microscope.

  FIG. 6 is a diagram schematically showing measurement by a laser microscope of the surface of the developing roller after surface polishing by a rubber roller mirror finisher. This figure shows the prototype developing roller 13n, its measurement region (measurement plane area) S0, and the objective lens 62 of the laser microscope.

  FIG. 7 is a diagram for explaining the uneven surface area obtained by measurement with a laser microscope. The figure shows, as an example, a hemispherical measurement object 63 that is easy to understand, and an enlarged view 63 'of the measurement area. In the measurement by the laser microscope, all the portions that are actually exposed as shown by the arrows d and e in FIG. 7 are compared with the measurement plane area S0 in FIG. The area is measured.

The area of all the portions that are actually exposed in appearance is calculated as a concavo-convex surface area S by a computer connected to the laser microscope.
The area ratio S / S0 shown in FIG. 5 is “uneven surface area S ÷ measured plane area S0”. If the measurement surface is a completely smooth surface, S / S0 = 1, and if there are irregularities, S / S0 = N (N> 1) depending on the degree of the irregularities.

  The developing roller 13n having the area ratio S / S0 thus obtained is subjected to a printing test using the above-described printer 1 in a laboratory environment up to an image density of 1.7% and two sheets intermittently up to UT (under toner). It was. In the printing test, all solid images were output as sample images on A3 paper when printing 0 sheets, printing 1000 sheets, printing 3000 sheets, printing 5000 sheets, and UT.

  In the solid follow-up density AVE column shown in FIG. 5, in the above-described solid image printing on the A3 size paper, 30 points in the printing area after the first turn of the developing roller are X-Rite (foreign color difference meter, sales Distributor measured with Nihon Flat Plate Equipment Co., Ltd.), the average value was taken as the solid follow-up density, and the average of the solid follow-up density of the sample images from 1000 to UT of the density was taken as the solid follow-up ability. The concentration is shown as AVE.

  In the visual field for followability, the evaluation of the toner transportability, that is, whether the solid followability is good or bad, is indicated by “O”, “Δ”, or “X” by visually checking the degree of density unevenness. . In other words, the evaluation criteria are “O” if there is no density unevenness and no problem, “Δ” if there is a slight density unevenness but no problem in terms of product quality, and “×” if obvious density unevenness occurs. It has become.

  Further, the Rz column shows an Rz value which is a ten-point average roughness for comparison. As detection conditions for the ten-point average roughness, the detector has a measurement magnification of 1000 times, an evaluation length L = 2.5 mm, a resolution L / 8000, a feed length of 0.1. mm / s, tip radius = 2 μ diamond, measuring force is 0.7 mN.

The abrasive tape column shows the count of the abrasive tape.
In the evaluation table of FIG. 5, as shown in the follow-up visual observation column, the prototype developing roller 13n whose evaluation was “◯” and “Δ” is a prototype whose material number is shown in Examples 1 to 8, These were prototype developing rollers having a solid followability density AVE of 1.3 or more.

In addition, when the solid follow-up density AVE was less than 1.3, the occurrence of a solid due to the poor solid follow-up ability was clearly observed.
As can be seen from the evaluation table of FIG. 5, the area ratio S / S0 of the prototype developing roller 13n having a solid follow-up density AVE of 1.3 or more is 2.37 or more. That is, if the area ratio S / S0 = 2.37 or more, it is considered that there is no problem in the solid followability.

  FIG. 8 is a characteristic diagram showing the relationship between the solid follow-up density AVE and the area ratio S / S0. In the characteristic diagram of the figure, the horizontal follow-up concentration AVE is taken on the horizontal axis and the area ratio S / S0 is taken on the vertical axis, and the solid follow-up concentration AVE obtained from the evaluation table of FIG. This is an approximate curve obtained from the corresponding plot of S0.

  As can be seen from this characteristic diagram, the solid followability deteriorates as the area ratio S / S0 decreases, and the solid followability improves as the area ratio S / S0 increases. The solid follow-up density AVE at which the area ratio S / S0 is 2.37 and the visual evaluation is “Δ” or more is 1.3 or more.

  FIG. 9 is a diagram showing the relationship between the area ratio S / S0 and the ten-point average roughness Rz obtained from the evaluation table of FIG. In the figure, the horizontal axis indicates the ten-point average roughness Rz, and the vertical axis indicates the area ratio S / S0. Further, the black circle plots show Examples 1 to 8 of the developing rollers that were evaluated well, and the white triangle plots show Comparative Examples 1 to 14 of the developing rollers that were evaluated poorly.

  As can be seen from FIG. 9, the range of ten-point average roughness Rz = 4.25-5.55 includes not only examples of developing rollers with good evaluation but also comparative examples of developing rollers with poor evaluation. Scattered. That is, it can be seen that the solid followability cannot be judged from the value of the ten-point average roughness Rz.

  FIG. 10 is a chart in which the data of the chart of the evaluation test results are rearranged in descending order of the area ratio S / S0. The sample numbers in the figure are only shown in ascending order from the top to the bottom, and are irrelevant to the numbers of the examples or comparative examples in the sample column of FIG.

  As shown in sample numbers 1 to 8 in FIG. 10, the solid follow-up concentration AVE is substantially proportional to the size of the area ratio S / S0 except for the sample number 5. On the other hand, the value of the ten-point average roughness Rz shows a variation regardless of the size of the area ratio S / S0. That is, it can be seen from the chart shown in FIG. 10 that the solid followability cannot be judged from the value of the ten-point average roughness Rz.

  As described above, the solid follow-up density AVE is substantially proportional to the value of the area ratio S / S0, and even with a developing roller having the same Rz surface state, if the S / S0 value becomes large regardless of the Rz value, the toner conveyance is performed. The force also increases, affecting the toner follow-up density.

  Therefore, regardless of the Rz value, when the uneven surface area of the developing roller is 2.37 or more, the amount of toner held on the developing roller is optimized, and the toner transport amount of the developing roller is set appropriately. It turns out to be.

  Although NBR is used as the rubber material for the developing roller, the present invention is not limited to this, and the present invention can naturally be applied to all rubber materials that can be used for the developing roller such as urethane.

1 is a cross-sectional view illustrating an internal configuration of a color image forming apparatus (printer) according to Embodiment 1 of the present invention. 1 is an external perspective view of an image forming apparatus (printer) in Embodiment 1. FIG. 1 is a circuit block diagram of an image forming apparatus (printer) in Embodiment 1. FIG. FIG. 2 is a side cross-sectional view illustrating in detail a configuration of a main part of the image forming unit in Embodiment 1. 6 is a table showing evaluation test results of toner followability after surface polishing by a rubber roller mirror finisher of a developing roller in Embodiment 1. It is a figure which shows typically the measurement by the laser microscope of the developing roller surface after the surface grinding | polishing process by the rubber roller mirror surface finishing machine in Embodiment 1. FIG. It is a figure explaining the uneven | corrugated | grooved part surface area obtained by the measurement by a laser microscope. FIG. 6 is a characteristic diagram showing a relationship between a solid follow-up density AVE and an area ratio S / S0. It is a figure which shows the relationship between area ratio S / S0 obtained from an evaluation table | surface, and ten-point average roughness Rz. It is the chart which rearranged the data of the chart of an evaluation test result in an order from the thing with large area ratio S / S0.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer 2 Image formation part 3 Duplex printing conveyance unit 4 Paper feed part 5 (5-1, 5-2, 5-3, 5-4) Image formation unit DU Drum unit TU Toner unit 6 Photosensitive drum 7 Cleaner 8 Charging Roller 9 Print head 10 Conveying belt 11 Transfer device 12 Developing container 13 Developing roller 13n (n = 1, 2, 3,...) Prototype developing roller 14 Paper feed roller 15 Paper feed cassette 16 Guide roller pair 17 Guide path 18 Feed Feed roller pair 19 Standby roller pair 20 Mounting portion cover 21 MPF tray 22 Paper feed roller 23 Drive roller 24 Driven roller 25 Fixing unit 26 Heat roller 27 Pressure roller 28 Oil application roller 29 Switching plate 31 Unloading roller pair 32 Side discharge port 33 Conveyance Roller pair 34 Paper discharge roller pair 35 Paper discharge unit 36a to 36e Conveyance roller 37 Concentration sensor 38 Upper part of the apparatus main body 39 Lower part of the apparatus main body 41 Operation panel 41a Key operation part 41b Display part 42 Front cover 43 Controller 44 Interface controller (I / F)
45 Printer controller (PR_CONT)
46 Printer Printing Unit 47 CPU
48 ROM
49 Frame memory 49M, 49C, 49Y, 49K Storage area 51 EEPROM
52 Toner 53 Stirring Member 54 Supply Roller 55 Doctor Blade 56 Squee Sheet 57 Squee Sheet Bias Power Supply 58 Sealing Member 59 Developing Roller Bias Power Supply 61 Toner Bias Power Supply 62 Laser Microscope Objective Lens S0 Measurement Area (Measurement Plane Area)
S Measurement uneven surface area 63 Measurement object 63 'Measurement area enlarged view

Claims (1)

Development used in a developing method that visualizes an electrostatic latent image selected from a rubber-like roller having irregularities formed on the surface based on a polishing process and held on a latent image carrier with a non-magnetic one-component toner. A method for selecting rollers,
The peripheral surface is observed using a laser microscope, and when the area of the measurement plane of the peripheral surface is S0 and the uneven surface area in the measurement plane region is S, a roller having S / S0 of 2.37 or more is selected . And a developing roller sorting method.