JP5489399B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus for transferring a toner image of an intermediate transfer member to a recording material that is nipped and conveyed by an intermediate transfer member and a transfer rotator, and more specifically, the length in the conveyance direction of an output image formed on the recording material The present invention relates to control for correcting the above.

  Each color toner image formed on the image carrier is primarily transferred to the intermediate transfer member and superimposed, and then secondary transfer is performed from the intermediate transfer member to a recording material sandwiched and conveyed between the intermediate transfer member and the transfer rotating member. Full-color image forming apparatuses have been put into practical use.

  In recent years, an elastic layer having an elastic coefficient lower than that of the substrate has been formed on the surface side of the substrate of the intermediate transfer member so as to be compatible with a wide variety of recording materials. The elastic layer deforms following the irregularities on the surface of the recording material, and uniformly contacts the toner image and the recording material.

  In recent years, a release layer having a low friction coefficient has been formed on the surface of the transfer rotator to facilitate the removal of the toner adhering to the surface of the transfer rotator. The release layer facilitates scraping off the toner adhering to the surface of the transfer rotator and prevents the toner from adhering to the back surface of the recording material from the transfer rotator.

  Patent Document 1 discloses a one-drum type intermediate transfer type image forming apparatus including a rotary developing device. Here, the scanning speed of the exposure device or the relative speed between the image carrier and the intermediate transfer belt is changed in accordance with the total number of image formations after the replacement of the intermediate transfer belt with a new one. The accompanying change in the length of the output image is reduced. If the intermediate transfer belt is crushed or worn as the usage history accumulates, the thickness of the intermediate transfer belt decreases, the surface speed decreases, and the length of the toner image transferred in the primary transfer direction becomes shorter. is there.

  Patent Document 2 discloses an image forming apparatus of a tandem type intermediate transfer system in which a plurality of toner image forming units are arranged in a straight section of an intermediate transfer belt. Here, a speed variation pattern in one rotation of the intermediate transfer belt is detected, and scanning exposure is performed according to the speed variation pattern, thereby preventing a color shift due to the speed variation of the intermediate transfer belt.

  Patent Document 3 discloses an image forming apparatus that detects a friction coefficient of an intermediate transfer belt and feeds back to a cleaning condition of the intermediate transfer belt. By detecting the current of the driving motor of the intermediate transfer belt and referring to the current-friction coefficient table, the friction coefficient of the intermediate transfer belt is obtained.

Japanese Patent Laid-Open No. 11-109827 JP 2004-102039 A JP 2005-249896 A

  When the transfer part is formed with an intermediate transfer member having an elastic layer and a transfer rotating member having a release layer, the length of the output image formed on the recording material in the conveying direction increases as the use history of the intermediate transfer member increases. Was found to be shorter (see Table 1). This is because the frictional force of the intermediate transfer member starts to decrease immediately after the replacement of a new one, and the holding and conveying force in the transfer portion gradually becomes insufficient, and the rate at which the recording material slips at the transfer portion increases.

  Therefore, as disclosed in Patent Document 1, the length of the output image formed in the recording material in the conveyance direction can be controlled in accordance with the total usage time after replacement of a new intermediate transfer belt and the total number of image formed sheets. was suggested.

  However, it has been found that if the control is simply performed according to the total number of images formed, the control error increases depending on the type of image formed. This is because the coefficient of friction of the intermediate transfer belt differs between a case where a monochrome character image with a small amount of applied toner is continuously formed and a case where a full color image with a large amount of applied toner is continuously formed even if the total number of images formed is the same. It was also confirmed that depending on the type of recording material, the friction coefficient of the intermediate transfer belt did not increase or decreased even when the total number of image formations increased.

  Therefore, it has been proposed to control the length of the output image by measuring the friction coefficient of the intermediate transfer belt and more accurately estimating the nipping and conveying force of the transfer portion.

  However, when the friction coefficient is measured depending on the driving force as shown in Patent Document 3, a large error may occur in the measured value of the friction coefficient of the intermediate transfer belt. This is because the driving force of the intermediate transfer belt is greatly influenced by factors other than the friction coefficient of the intermediate transfer belt, such as the type, thickness, and environmental conditions of the recording material.

  If a contact-type frictional force measuring device is provided on the intermediate transfer belt to measure the friction coefficient, the driving load increases, resulting in a speed fluctuation of the intermediate transfer belt, or an increase in power consumption. In a downsized image forming apparatus, it is difficult to find a room for installing a new frictional force measuring device.

  SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of accurately estimating the nipping / conveying capability of a transfer unit and accurately controlling the length of an output image in the conveying direction without providing a dedicated friction force measuring device. Yes.

The image forming apparatus of the present invention includes a rotatable photosensitive member, an exposure unit that forms an electrostatic image on the charged photosensitive member, and a toner image by attaching toner to the electrostatic image formed on the photosensitive member. A developing means, an intermediate transfer body having an elastic layer to which the toner image of the photosensitive member is transferred, an intermediate transfer body driving means for rotationally driving the intermediate transfer body, and pressed toward the intermediate transfer body. A transfer roller having a release layer on the surface for electrostatically transferring the toner image of the intermediate transfer member to the recording material while nipping and conveying the recording material, and rotating the transfer roller Transfer roller driving means for driving. Further, the gloss level detecting means for detecting the gloss level of the surface of the intermediate transfer body, and the gloss level of the surface of the intermediate transfer body by the gloss level detecting means according to the detection result of the gloss level of the intermediate transfer body. When the glossiness detection result is the first glossiness so that the length of the toner image on the intermediate transfer body in the rotational direction of the intermediate transfer body is changed , the electrostatic image formed on the photoconductor Scanning line interval setting means for setting the scanning line interval in the rotation direction of the photosensitive member to be wider than the scanning line interval when the glossiness detection result is a second glossiness higher than the first glossiness. Prepare.
An image forming apparatus according to another aspect includes an image carrier on which a toner image is formed, an intermediate transfer member having an elastic layer onto which the toner image on the image carrier is transferred, and an intermediate transfer that rotationally drives the intermediate transfer member A release layer on the surface for electrostatically transferring the toner image of the intermediate transfer body to the recording material while sandwiching and conveying the recording material by being pressed against the intermediate transfer body and the body driving means And a transfer roller driving means for rotationally driving the transfer roller. And, when the glossiness detecting means for detecting the glossiness of the surface of the intermediate transfer body and the detection result of the glossiness of the surface of the intermediate transfer body by the glossiness detecting means is the first glossiness, the transfer roller Drive speed setting means for setting the drive speed of the drive means faster than the drive speed when the glossiness detection result is a second glossiness higher than the first glossiness.

  Since the image forming apparatus of the present invention sets the control amount of the adjusting unit according to the glossiness of the intermediate transfer member, the recording in the transfer unit is more than the case where it is simply set according to the total use time and the total number of image formed sheets. The ability to pinch and convey the material can be accurately reflected in the control amount. As will be described later, the glossiness of the intermediate transfer member has a strong correlation with the friction coefficient of the intermediate transfer member and with the contraction rate (image magnification) of the image length in the initial state and the accumulated state of the use history. Because it has sex. Therefore, rather than relying on the total number of image formations, it is possible to accurately estimate the amount of contraction of the image length that accompanies the accumulation of image formation, and to accurately control the length of the output image in the conveyance direction. The reproducibility of height can be improved.

  Hereinafter, some embodiments of the present invention will be described in detail with reference to the drawings. As long as the glossiness of the intermediate transfer belt is detected and the expansion / contraction ratio of the image is adjusted, the present invention is also realized in another embodiment in which part or all of the configuration of each embodiment is replaced with the alternative configuration. Is possible.

  Accordingly, the image forming apparatus can be implemented not only in the tandem type intermediate transfer system but also in the one-drum type intermediate transfer system.

  In the first embodiment, only the main part relating to the formation / transfer of the toner image will be described. However, in the present invention, a printer, various printing machines, a copier, a FAX, It can be implemented in various applications such as a multifunction machine.

  In addition, about the general matter of the image forming apparatus shown by patent document 1, 2, and 3, illustration is abbreviate | omitted and the overlapping description is abbreviate | omitted.

<First Embodiment>
FIG. 1 is an explanatory diagram of a configuration of the image forming apparatus according to the first embodiment, and FIG. 2 is an explanatory diagram of a configuration of an image forming unit and a secondary transfer unit.

  As shown in FIG. 1, an image forming apparatus 100 according to the first embodiment is a full-color copying machine that forms an image of a document read by an image reading apparatus 100R with a printer unit 100P. The printer unit 100P is a tandem type intermediate transfer system in which four image forming units SA, SB, SC, and SD are arranged in a straight section of the intermediate transfer belt 31.

  In the image forming unit SD, a yellow toner image is formed on the photosensitive drum 11d, and is primarily transferred to the intermediate transfer belt 31 in the primary transfer unit Td. In the image forming unit SC, a magenta toner image is formed on the photosensitive drum 11c, and is primary-transferred over the yellow toner image of the intermediate transfer belt 31 in the primary transfer unit Tc. In the image forming portions SB and SA, a cyan toner image and a black toner image are formed on the photosensitive drums 11b and 11a, respectively, and are similarly primarily transferred to the intermediate transfer belt 31 in the primary transfer portions Tb and Ta.

  The four-color toner images primarily transferred to the intermediate transfer belt 31 are conveyed to the secondary transfer portion T2 and are collectively secondary transferred to the recording material P taken out from the paper feed cassette 21 or the paper feed tray 27.

  The recording material P onto which the toner image has been secondarily transferred by the secondary transfer portion T2 is heated and pressed by the fixing device 40 to fix the toner image on the surface, and then the inner discharge roller 44 and the outer discharge roller 45. And then loaded onto the discharge tray 48.

  The separating device 23 separates the recording material P drawn from the sheet feeding cassette 21 by the pickup roller 22 one by one and sends it to the registration roller 25.

  The registration roller 25 receives and waits for the recording material P in the stopped state, nipping and conveying the recording material P in synchronization with the toner image carried on the intermediate transfer belt 31, and feeding it to the secondary transfer portion T2. .

  The intermediate transfer belt 31 superimposes and carries the toner images of the respective colors, which are primary transferred in order at the primary transfer portions Ta, Tb, Tc, and Td, and conveys them to the secondary transfer portion T2.

The intermediate transfer belt 31 is wound around a driving roller 32, a tension roller 33, and a backup roller 34 as intermediate transfer body driving means , and rotates in a direction indicated by an arrow R2 at a predetermined process speed.

  The secondary transfer roller 36 is pressed against the backup roller 34 via the intermediate transfer belt 31 to form a secondary transfer portion T2 that is an example of a transfer portion between the intermediate transfer belt 31 and the secondary transfer roller 36. .

  The backup roller 34 bends the path of the intermediate transfer belt 31 on the downstream side of the secondary transfer portion T2, and separates the recording material P attached to the intermediate transfer belt 31 by curvature.

  The fixing device 40 forms a fixing portion T3 by pressing a pressure roller 41b against a fixing roller 41a having a heat source such as a halogen heater inside by a spring bias. The fixing unit T3 fixes the toner image on the surface of the recording material P by nipping and conveying the recording material P onto which the toner image has been secondarily transferred while being heated and pressurized.

  The cleaning device 19 rubs and removes the transfer residual toner on the intermediate transfer belt 31 that has passed through the secondary transfer portion T2 without being secondarily transferred to the recording material P, by a cleaning blade.

  The image forming units SA, SB, SC, and SD are configured in the same manner except that the toner colors used in the attached developing devices 14a, 14b, 14c, and 14d are different from black, cyan, magenta, and yellow. Hereinafter, the black image forming unit SA will be described, and the other image forming units SB, SC, and SD will be described by replacing “a” at the end of the reference numerals with “b”, “c”, and “d”.

  As shown in FIG. 2, the image forming unit SA includes a charging device 12a, an exposure device 13a, a developing device 14a, a primary transfer roller 35a, and a cleaning device 15a around the photosensitive drum 11a.

A photosensitive drum 11a as a photosensitive member has a negatively charged photosensitive layer formed on the outer peripheral surface of an aluminum cylinder connected to a ground potential. The photoconductive drum 11a is rotated in the direction of the arrow R1 with the driving force transmitted to one end thereof.

  The charging device 12a irradiates the photosensitive drum 11a with negatively charged particles generated by corona discharge, and charges the surface of the photosensitive drum 11a to a uniform negative potential.

  The power source D3 applies a voltage to the discharge electrode of the charging device 12a to generate corona discharge.

An exposure device 13a as an exposure unit scans a scanning beam image data obtained by developing a black separated color image with a polyhedral mirror, and scans the surface of the charged photosensitive drum 11a with an electrostatic image of the image. Write.

The developing device 14a as a developing unit supplies toner charged with a negative polarity by mixing and stirring to a magnetic carrier to the photosensitive drum 11a to reversely develop the electrostatic image.

  The developing sleeve 14s carries the magnetic carrier and the toner in a spiked state, rotates in the counter direction with respect to the photosensitive drum 11a, and rubs the surface of the photosensitive drum 11a with the spiked toner.

  The power source D4 applies a voltage obtained by superimposing an AC voltage to a negative DC voltage to the developing sleeve 14s, and attaches toner to the exposed portion of the electrostatic image that has a relatively positive polarity to form a toner image. .

  The primary transfer roller 35 a is in pressure contact with the photosensitive drum 11 a via the intermediate transfer belt 31 to form a primary transfer portion Ta between the photosensitive drum 11 a and the intermediate transfer belt 31.

  The power source D1 applies a positive direct current voltage to the primary transfer roller 35a to primarily transfer the toner image on the photosensitive drum 11a to the intermediate transfer belt 31 passing through the primary transfer portion Ta.

  The cleaning device 15a removes the transfer residual toner that passes through the primary transfer portion Ta and remains on the surface of the photosensitive drum 11a with a cleaning blade, and prepares for the next toner image formation.

  The secondary transfer roller 36 is pressed against the backup roller 34 via the intermediate transfer belt 31 to form a secondary transfer portion T <b> 2 between the intermediate transfer belt 31 and the secondary transfer roller 36. The backup roller 34 is connected to the ground potential, and the secondary transfer roller 36 is connected to the power source D2.

  The power source D2 applies a positive voltage having a polarity opposite to the charging polarity of the toner to the secondary transfer roller 36, so that the four color toner images carried on the intermediate transfer belt 31 are collectively applied to the recording material P. Next transfer.

  In the image forming apparatus 100, a control image is formed at an interval between images (so-called paper interval), read by the optical sensor 60, and fed back to the image forming conditions of the image forming unit SA (SB, SC, SD).

  A patch image of each color is formed on the photosensitive drum 11a (11b, 11c, 11d) and transferred to the intermediate transfer belt 31, and the detection result of the patch image by the optical sensor 60 is fed back to the exposure intensity and development conditions, and each color density is Ensures stability.

  A registration mark image of each color is formed on the photosensitive drum 11a (11b, 11c, 11d) and transferred to the intermediate transfer belt 31, and the detection result of the registration mark image by the optical sensor 60 is fed back to the exposure timing so that each color overlay accuracy Is increasing.

  Even if these control images pass through the optical sensor 60 and are transported to the secondary transfer portion T2, they are not transferred to the recording material. Therefore, the control images are secondarily transferred to the secondary transfer roller 36 and the next recording material P is backed. Make it dirty. For this reason, the secondary transfer roller cleaning device 50 is attached to the secondary transfer roller 36 so that the control image attached to the secondary transfer roller 36 is quickly removed so as not to reach the secondary transfer portion T2. .

  The secondary transfer roller cleaning device 50 slides the fur brush 51 against the secondary transfer roller 36 to remove the toner transferred to the secondary transfer roller 36 at the secondary transfer portion T2.

  The fur brush 51 is formed by flocking a carbon dispersion type nylon fiber having a resistance value of 10 MΩ on a metal roller, and is driven to rotate in the counter direction with respect to the secondary transfer roller 36.

  The metal roller 52 is formed of an aluminum cylindrical material and is rotationally driven with respect to the fur brush 51 at a substantially equal circumferential speed in the width direction.

  The cleaning blade 53 is formed of a urethane rubber blade, and is disposed in contact with the metal roller 52 in the counter direction.

  The power source D <b> 5 applies a voltage of +700 V (ground potential) to the metal roller 52 to make the potential of the fur brush 51 higher on the positive polarity side than the secondary transfer roller 36.

  The negatively charged toner is electrostatically attached from the secondary transfer roller 36 to the fur brush 51, moves to the metal roller 52, and is scraped off to the housing 54 by the cleaning blade 53.

  The control unit 80 includes a CPU (not shown) for controlling the operation of the mechanism of the image forming unit SA, a control board, a motor drive board, and the like.

<Intermediate transfer belt>
FIG. 3 is an explanatory diagram of the configuration of the intermediate transfer belt.

  The image forming apparatus 100 employs an elastic ITB (intermediate transfer belt) having a soft surface for the intermediate transfer belt 31 in order to cope with diversified recording materials. The elastic ITB prevents the transfer failure of the recording material P having surface irregularities, and prevents a transfer failure called “middle loss” that is likely to occur on coated paper or OHP paper.

  However, since the elastic ITB has a high adhesion to the surface of the recording material P, the surface friction coefficient is higher than that of a conventional resin belt. Conventional resin belts include polycarbonate (PC), polyethylene terephthalate resin film (ETFE), polyvinylidene fluoride resin film (PVdF), polyimide (PI), and the like.

  As shown in FIG. 3, the intermediate transfer belt 31 has a three-layer configuration of a base material 311, an elastic layer 312, and a coat layer 313, and has a total thickness of about 360 μm.

  The base material 311 is made of a conductive polyimide resin material (PI) having a thickness of 80 μm to 90 μm.

  The elastic layer 312 which is an example of the elastic layer is formed by laminating 200 μm to 300 μm of chloroprene rubber on the base material 311 and has a JISA hardness of 60 degrees. The hardness of the elastic layer 312 is suitably about 40 to 80 degrees in order to achieve the effect (deformation effect) as the elastic layer. The elastic layer 312 follows the irregularities on the surface of the recording material and deforms to ensure contact between the toner image carried on the intermediate transfer belt 31 and the surface of the recording material. In addition, the local increase in pressure in the central region of the line width of the toner image is dispersed to prevent “missing” transfer failure that is likely to occur on coated paper or OHP paper that is surface-coated.

  The coat layer 313 ensures the releasability of the supported toner particles and recording material, and is the outermost layer having a thickness of about 5 μm to 15 μm in which a fluororesin is dispersed in a polyurethane resin binder.

The overall resistance of the intermediate transfer belt 31 is adjusted so that the volume resistivity is 1 × 10 ⁹ to 1 × 10 ¹¹ Ω · cm, and the surface resistivity is adjusted to 1 × 10 ¹¹ to 1 × 10 ¹³ Ω / □. .

<Secondary transfer roller>
FIG. 4 is an explanatory diagram of the configuration of the secondary transfer roller, and FIG. 5 is an explanatory diagram of resistance measurement of the secondary transfer roller.

  The surface of the secondary transfer roller 36 is coated with a resin having a good releasability containing a fluororesin so that the secondary transfer roller cleaning device 50 can sufficiently clean the control image. For this reason, the surface of the secondary transfer roller 36 has a smaller coefficient of static friction than that of a conventional uncoated solid rubber or sponge rubber.

As shown in FIG. 4, the secondary transfer roller 36 as a transfer roller is formed in a cylindrical shape having an outer diameter of 24 mm and a length of 340 mm, and includes a metal core 361, a sponge layer 362, a solid layer 363, and a coat layer 364. It has a four-layer structure.

  The metal core 361 is a stainless steel round bar having an outer diameter of 12 mm that also serves as the rotating shaft of the secondary transfer roller 36.

  The sponge layer 362 is an elastic layer having a sponge structure formed of nitrile rubber (NBR) and hydrin rubber (ECO) to a thickness of 4 mm to 5 mm.

  The solid layer 363 is a solid structure elastic layer formed of nitrile rubber (NBR) and hydrin rubber (ECO) to a thickness of 1 mm to 2 mm. The solid layer 363 smoothes the surface of the sponge structure of the sponge layer 362 and facilitates toner removal by the secondary transfer roller cleaning device 50. This is because the toner trapped in the sponge tissue is unlikely to contact the fur brush 51.

  The coating layer 364, which is an example of a release layer, is a coating layer having a thickness of 10 to 30 μm in which a fluororesin is dispersed in a polyurethane resin binder. 50 facilitates cleaning. The coat layer 364 can prevent toner particles and external additives contained in the developer from adhering to the surface of the secondary transfer roller 36 over a longer period than the exposed surface of the solid layer 363.

As shown in FIG. 5, with the secondary transfer roller 36 in contact with the aluminum cylinder S6 having an outer diameter of 30 mm, the current was detected by the ammeter A6 by applying 2000 V from the power source D6. The resistance value of the secondary transfer roller 36 is calculated from the detected current and the applied voltage. The resistance from the metal core 361 to the coat layer 364 shown in FIG. 4 is adjusted to 1 × 10 ⁶ to 1 × 10 ⁹ Ω.

  The hardness of the secondary transfer roller 36 is adjusted to 30 to 45 degrees in terms of Asker C hardness measured under a load of 9.8 N. Thereby, the nip width (length in the rotation direction) of the secondary transfer portion T2 shown in FIG. 2 is secured.

<Friction coefficient of secondary transfer area and expansion / contraction of transferred image>
6 is an explanatory diagram of the frictional force acting on the recording material passing through the secondary transfer portion, FIG. 7 is an explanatory diagram of a measurement image used for measuring the length of the output image in the transport direction, and FIG. It is explanatory drawing of the measurement of the static friction coefficient of a transfer belt.

  As shown in FIG. 6, the recording material P has a friction force Fμs1 obtained by multiplying the pinching force F of the secondary transfer portion T2 by the friction coefficient μs1 of the intermediate transfer belt 31, and the friction force of the secondary transfer roller 36 to the pinching force F. It is conveyed with a frictional force Fμs2 multiplied by μs2. The recording material P is nipped and conveyed by the intermediate transfer belt 31 and the secondary transfer roller 36, and at the same time, is subjected to a frictional load on conveyance guides upstream and downstream of the secondary transfer portion T2.

  In the image forming apparatus 100, since the friction coefficient μs2 of the secondary transfer roller 36 is smaller than the friction coefficient μs1 of the intermediate transfer belt 31, the intermediate transfer belt 31 is dominant in the nipping and conveying force (Fμs1 + Fμs2) of the secondary transfer portion T2. It is.

The secondary transfer portion T2 has a total pressure of 64 N, a rubber length of the secondary transfer roller 36 of 340 mm (0.34 m), a nip width of 5 mm (0.005 m), and a pressure per unit area of 3.7 × 10 ⁵ N / m ^2. Designed to.

Here, when the pressure of the secondary transfer portion T2 is less than 2.0 × 10 ⁵ N / m ² , the recording material cannot be sufficiently carried and conveyed, and depending on the density and area ratio of the toner image formed on the recording material P, There arises a problem that the length of the output image changes.

On the other hand, when the pressure of the secondary transfer portion T2 exceeds 7.0 × 10 ⁵ N / m ² , when the recording material is thin paper, wrinkle-like deformation occurs from the center in the conveyance direction of the recording material to the rear end. It becomes easy to do.

Therefore, the pressure of the secondary transfer portion T2 are preferably, 2.0 × ¹⁰ 5 N / ^{above, 7.0 × 10 5 N / m} 2 or less, more ^{preferably, 3.0 × 10 5 N / m} 2 As described above, it is set to 5.0 × 10 ⁵ N / m ² or less.

As shown in FIG. 3, the intermediate transfer belt 31 having the elastic layer 312 has a higher surface friction coefficient μs1 than the intermediate transfer belt (base material 311 + coat layer 313) of the comparative example in which the elastic layer 312 is omitted. The intermediate transfer belt of the comparative example is resin ITB (PI), which is the same as the base material 311 of the intermediate transfer belt (elastic ITB) 31, and has a volume resistivity of 1 × 10 ⁹ to 10 ¹¹ Ω · cm, surface The resistivity is controlled to 1 × 10 ¹¹ to 10 ¹³ Ω / □.

  Since the intermediate transfer belt of the comparative example has a thickness of 80 to 90 μm and is considerably thinner than the total thickness of the intermediate transfer belt 31 of about 360 μm, the peripheral speed of the intermediate transfer belt at the primary transfer portion Ta and the secondary transfer portion T2 Is different from that of the first embodiment. For this reason, the diameter of the driving roller 32 shown in FIG. 1 is increased, and the surface speed of the intermediate transfer belt of the comparative example in the secondary transfer portion T2 is matched with that when the intermediate transfer belt 31 is mounted.

As shown in FIG. 4, the secondary transfer roller 36 on which the coat layer 364 is formed has a lower surface friction coefficient than the secondary transfer roller (sponge layer 362 + solid layer 363) of the comparative example in which the coat layer 364 is omitted. . In the secondary transfer roller of the comparative example, a single conductive sponge layer (about 6 mm) is formed on a φ12 mm metal core, and the resistance is 1 × 10 ⁶ to 1 × 10 ^{9 in the same} manner as the secondary transfer roller 36. It adjusted to (omega | ohm) (at the time of 2000V application). The hardness was set to substantially the same value as that of the secondary transfer roller 36 having the coat layer 364.

  A comparative experiment was conducted to compare the difference in magnification of the transferred image with respect to the difference in the combination of the type and consumption state of the intermediate transfer belt and the type of the secondary transfer roller.

  Table 1 shows the measurement result of the magnification difference of the transferred image along with the measurement result of the friction coefficient. The friction coefficient is a measurement result of the static friction coefficient. In the expansion / contraction of the transferred image, the length in the transport direction of the output image formed through the transfer / fixing is measured, and the magnification with respect to the length of the original image data is calculated.

  The length of the output image in the conveyance direction was measured manually by forming an image of the measurement image GA shown in FIG. 7 on a standard recording material determined by the applicant. The standard recording material has a CLC paper basis weight of 81.4 g / m 2 and an A3 size (width 297 mm × length 420 mm).

  As shown in FIG. 7, a 10 mm square grid image of Bk monochromatic color is formed on the entire surface of the standard recording material with a margin of 2 mm at the leading edge, and the leading and trailing edges of 41 horizontal lines from the first horizontal line to the last horizontal line at the rear end are formed. The length of was measured. When there is no magnification variation and is 100%, the measured value is 400 mm, and the measured value changes due to the magnification variation. However, the method for measuring the length of the output image in the conveyance direction is not limited to this method.

  As shown in FIG. 8, the friction coefficient μs1 of the intermediate transfer belt 31 is measured by winding the probe 315 of a portable friction meter (HEIDON tribogear μsType 94i) on the surface of the intermediate transfer belt 31 around a φ24 metal roller 314. .

  The friction coefficient μs2 of the secondary transfer roller 36 was measured by bringing the secondary transfer roller 36 into direct contact with the surface of the probe 315 of the same portable friction meter.

  In Table 1, in the secondary transfer portion T2 using the comparative secondary transfer roller, the expansion / contraction magnification of the transferred image was uniformly 100%. In other words, regardless of the type of the intermediate transfer belt 31 (comparative example) or the state of wear, the holding and conveying force of the secondary transfer portion T2 with no recording material slipping is ensured.

  In Table 1, in the secondary transfer unit configured by similarly pressing the comparative example secondary transfer roller against the intermediate transfer belt of the comparative example, the holding and conveying force of the secondary transfer unit T2 is insufficient, and the recording material Slip increases. However, since the friction coefficient μs1 of the intermediate transfer belt 31 does not change so much as the usage history accumulates, there is little change in the length of the transfer image in the conveyance direction.

  In Table 1, in the secondary transfer portion T2 configured by pressing the secondary transfer roller 36 against the intermediate transfer belt 31, the friction coefficient μs1 of the intermediate transfer belt 31 increases as the use history of the intermediate transfer belt 31 accumulates. Change. For this reason, as the usage history of the intermediate transfer belt 31 is accumulated, the length of the transfer image in the conveyance direction changes greatly.

  That is, in the case of the secondary transfer roller of the comparative example having a sufficiently large friction coefficient μs2, the image magnification is stabilized regardless of the friction coefficient of the intermediate transfer belt 31. For this reason, if the image magnification is adjusted first, an image output can be obtained at a stable magnification all the way to the end.

  Further, even when the secondary transfer roller 36 having the coating layer 364 and a small friction coefficient is combined with the intermediate transfer belt of the comparative example in which the friction coefficient μs1 is not significantly different between the initial state and the end of life, the fluctuation of the image magnification is almost none. For this reason, if the image magnification is adjusted first, an image output can be obtained at a stable magnification all the way to the end.

  However, in the first embodiment in which the intermediate transfer belt 31 in which the friction coefficient μs1 is greatly different between the initial state and the end of life is combined with the secondary transfer roller 36 in which the coat layer 364 is formed and the friction coefficient μs2 is small, the image magnification of the first embodiment is reduced. Fluctuation increases.

  Therefore, even after the image magnification is adjusted using the measurement image shown in FIG. 7 in the initial state, the image magnification changes with the accumulation of image formation. Needs to be offset.

  Therefore, in the image forming apparatus 100 of the first embodiment, the image magnification is adjusted according to the output voltage of the optical sensor 60 that detects the surface of the intermediate transfer belt 31 that does not carry the toner image. This is because it has been experimentally confirmed that the output voltage of the optical sensor 60 (the glossiness of the intermediate transfer belt 31) has a strong correlation with the friction coefficient of the intermediate transfer belt 31.

<Glossiness and friction coefficient of intermediate transfer belt>
FIG. 9 is an explanatory diagram of the relationship between the cumulative number of image formations and the glossiness of the intermediate transfer belt, and FIG. 10 is an explanatory diagram of the relationship between the glossiness of the intermediate transfer belt and the image magnification. FIG. 11 is an explanatory diagram of the configuration of the optical sensor, and FIG. 12 is an explanatory diagram of the relationship between the output of the optical sensor and the glossiness of the intermediate transfer belt.

  The image magnification fluctuation that occurs in the process in which the recording material P passes through the secondary transfer portion T2 and the toner image is transferred has a high contribution ratio of the friction coefficient μs1 of the surface of the intermediate transfer belt 31. Since the intermediate transfer belt 31 always repeats the process of carrying and transporting the toner on the surface and cleaning the transfer residual toner, the surface property is likely to change with the accumulation of image formation. For this reason, as the intermediate transfer belt 31 is consumed, the nipping / conveying speed of the recording material P changes, and the image magnification changes.

  As shown in FIG. 9, the glossiness of the intermediate transfer belt decreases as the cumulative number of images formed increases. FIG. 9 shows the result of measuring the surface glossiness of the intermediate transfer belt 31 in the process of continuously forming a specific reference image without performing any image magnification control. The glossiness was measured using a handy gloss meter (PG1 incident angle 75 °) manufactured by Nippon Denshoku Industries Co., Ltd.

  As shown in FIG. 10, the image magnification of the output image formed on the recording material P decreases as the glossiness of the intermediate transfer belt 31 decreases. FIG. 10 was prepared using the measurement result of the image magnification and the measurement result of the glossiness of the image obtained in the experiment of FIG.

  As described with reference to Table 1, the reduction in the image magnification of the output image occurs with the reduction in the friction coefficient μs1 of the intermediate transfer belt 31 that dominates the nipping and conveying force of the recording material P in the secondary transfer portion T2. doing.

  Therefore, the change in the image magnification accompanying the accumulation of image formation is caused by the change in the friction coefficient μs1 of the intermediate transfer belt 31, and the friction coefficient μs1 has a strong correlation with the glossiness of the intermediate transfer belt 31.

  As shown in FIG. 11, in the first embodiment, a gloss meter that measures the gloss level of the surface of the intermediate transfer belt 31 is an optical sensor 60 that is an example of a gloss level detection unit and an example of a reflected light detection unit. It was made to substitute with. The optical sensor 60 is a regular reflection type infrared sensor composed of a light emitting element (infrared light emitting LED) 61 as a light emitter and a light receiving element (photodiode) 62 as a light receiver. The optical sensor 60 is standardized so that the glossiness is 85 when the output voltage is 4.5V.

  As shown in FIG. 12, the output voltage of the optical sensor 60 and the glossiness measured with the above-described handy gloss meter show a substantially linear correlation. Since the output voltage of the optical sensor 60 has linearity with respect to the glossiness of the surface of the intermediate transfer belt 31, the glossiness meter can be substituted for the optical sensor 60.

<Example 1>
FIG. 13 is a flowchart of initialization control, and FIG. 14 is a flowchart of image magnification adjustment control for each job.

  As shown in FIG. 2, in the first embodiment, when the service person executes the adjustment of the image magnification at the time of replacement of the intermediate transfer belt 31 or at an arbitrary time, thereafter, the output of the optical sensor 60 is changed for each job. Accordingly, the image magnification is automatically adjusted. Before shipping the image forming apparatus 100 or when the image forming apparatus 100 is replaced with a new intermediate transfer belt 31 in the market, the service person performs the following work.

  As shown in FIG. 13 with reference to FIG. 2, when an operation input indicating that the intermediate transfer belt 31 has been exchanged is made on the operation panel 81 (YES in S <b> 11), the control unit 80 activates the image forming apparatus 100. The pre-rotation is started (S13). When an operation input for adjusting the image magnification is performed on the operation panel 81 (YES in S12), the control unit 80 activates the image forming apparatus 100 and starts pre-rotation (S13).

  The control unit 80 detects regular reflection light by the optical sensor 60 on the surface of the intermediate transfer belt 31 that has been sufficiently cleaned by the cleaning device 19 without performing image formation, and measures glossiness as an initial measurement value. (S14). The control unit 80 initializes the glossiness of the intermediate transfer belt 31 recorded in the storage device 82. In initialization, first, glossiness measurement (output detection of the optical sensor 60) is performed, and the value is recorded in the storage device 82.

  The control unit 80 forms the measurement image GA shown in FIG. 7 in the fixing state by using the image forming condition of the initial setting value and the control amount of the image magnification of the initial setting value recorded in the storage device 82. Output (S15).

  When the measurement image GA is output, the serviceman manually measures the length from the front end to the rear end of the 41 horizontal lines formed at intervals of 10 mm (theoretical value), and the measured values are displayed on the operation panel. A numerical value is entered in the input box 81.

  When an operation to the effect that the numerical value input is completed is performed on the operation panel 81 (YES in S16), the control unit 80 compares the input measurement value with the image data and calculates the expansion / contraction magnification of the image (S18).

  The service person may set the output measurement image GA in the image reading apparatus 100R shown in FIG. 1 and operate the reading button of the operation panel 81 instead of the manual measurement.

  When the reading button is operated, the control unit 80 reads the set measurement image GA with the image reading device 100R (YES in S17), and the tip of 41 horizontal lines of the measurement image GA by the image analysis system. The length from to the rear end is automatically measured. Then, the expansion / contraction magnification of the image is calculated by comparing the automatic measurement value with the image data (S18).

  The controller 80 stops the pre-rotation (S19), and sets an adjustment amount as an initial setting value of the rotation speed of the polygon mirror that determines the scanning speed of laser writing when the exposure device 13a performs electrostatic image formation. Set (S20). Specifically, the initial setting value of the rotation speed of the polygon motor of the exposure apparatus 13a is changed. When the adjustment amount for increasing the rotation speed is set, the scanning line interval is shortened, the image magnification is lowered, and the image length in the transport direction of the recording material P is shortened. On the contrary, when the adjustment amount for decreasing the rotation speed is set, the interval between the scanning lines is increased, the image magnification is increased, and the image length in the conveyance direction of the recording material P is increased.

  The control unit 80 converts the glossiness and image magnification conversion table shown in FIG. 10 from the output value of the optical sensor 60 representing the glossiness of the initial intermediate transfer belt 31 and the actual measurement value of the expansion / contraction magnification measured with the measurement image GA. Is recorded in the storage device 82.

The control unit 80 serving as the scanning line interval setting means refers to the conversion table with the glossiness measurement value for each job and immediately calculates the image magnification, and calculates the control amount of the rotation speed of the polygon motor.

  As shown in FIG. 14 with reference to FIG. 2, when an image forming job is input (YES in S21), the control unit 80 activates the image forming apparatus 100 and starts pre-rotation (S22).

  The controller 80 detects regular reflection light on the surface of the intermediate transfer belt 31 that has been sufficiently cleaned by the cleaning device 19 without performing image formation, and measures glossiness (S23).

  The control unit 80 refers to the conversion table (FIG. 10) recorded in the storage device 82 to obtain the expansion / contraction magnification corresponding to the glossiness of the intermediate transfer belt 31 (S24).

  The control unit 80 sets a control amount (rotational speed of the polygon motor) of the exposure apparatus 13a (13b, 13c, 13d) according to the obtained expansion / contraction magnification (S25).

  The control unit 80 controls the exposure device 13a (13b, 13c, 13d) with the set control amount, and the image expanded or contracted according to the glossiness is recorded on the recording material P until the job is completed (YES in S27). Form (S26).

  That is, after the initialization of the glossiness / stretch ratio conversion table (FIG. 10) is completed, normal image formation becomes possible. The glossiness of the intermediate transfer belt 31 for each job input is monitored by the optical sensor 60, and the expansion / contraction magnification of the image is changed according to the friction coefficient of the intermediate transfer belt 31.

  In the first embodiment, at the timing of measuring the glossiness, the developing device 14a (14b, 14c, 14d) is stopped, and toner adhesion, commonly called “fog”, is removed to improve the measurement accuracy of the glossiness. ing. An averaging process is also performed so as not to excessively react to the abnormal output of the optical sensor 60.

  In the first embodiment, the expansion / contraction magnification of the image changes as shown in FIG. 10 as the glossiness of the surface of the intermediate transfer belt 31 changes. Therefore, the change in glossiness is detected by the optical sensor 60, and from the initial setting time. The rotational speed of the polygon motor is changed only to offset the fluctuation of the expansion / contraction magnification.

  However, if the control for determining the control amount according to the glossiness and adjusting the expansion / contraction magnification is continued for a long time, the length of the output image may not be reproduced as initially set.

  In order to cope with such a case, in the first embodiment, it is possible to perform initial setting control (FIG. 13: S12) similar to that at the time of initialization through the scanning panel at an arbitrary timing.

  As described above, the image forming apparatus 100 according to the first embodiment detects the control toner image t on the intermediate transfer belt 31 because the friction coefficient of the intermediate transfer belt 31 is larger than the friction coefficient of the secondary transfer roller 36. It has an optical sensor 60. In the first embodiment, control for changing the length in the moving direction of the image formed on the intermediate transfer belt 31 (changing the rotation speed of the polygon) according to the output of the existing optical sensor 60 is added. As a result, the length of the output image can be stably obtained from the new state of the intermediate transfer belt 31 to the end of its life.

<Example 2>
As shown in FIG. 1, the control of Example 2 performed using the image forming apparatus 100 of the first embodiment will be described.

  In Embodiment 1, the exposure device 13a (13b, 13c, 13d) is controlled to change the length of the toner image formed on the photosensitive drum 11a (11b, 11c, 11d) and output to the recording material P. Reproduce the length of the image.

  In the second embodiment, the length of the image output to the recording material P is adjusted by adjusting the rotation speed of the secondary transfer roller 36 without changing the control of the exposure device 13a (13b, 13c, 13d). Reproduced.

  In Example 2, the glossiness of the intermediate transfer belt 31 varies depending on the length of the toner image formed on the photosensitive drum 11a (11b, 11c, 11d) and the length of the toner image carried on the intermediate transfer belt 31. But it remains constant.

  Then, by adjusting the relative speed difference between the intermediate transfer belt 31 and the recording material, the length of the image formed on the recording material P in the conveyance direction is expanded and contracted. Specifically, by increasing the rotation speed of the secondary transfer roller 36, the passage time of the recording material P in the secondary transfer portion T2 is shortened to extend the length of the image. Conversely, by lowering the rotational speed of the secondary transfer roller 36, the passage time of the recording material P in the secondary transfer portion T2 is extended to shorten the length of the image.

As shown in FIG. 2, the control unit 80 serving as a drive speed setting unit sets a control amount of the rotation speed of the drive motor M <b> 2 of the secondary transfer roller 36 and expands / contracts according to the glossiness of the intermediate transfer belt 31. Is generated at the secondary transfer portion T2.

  The initial setting control shown in FIG. 12 and the control amount setting control for each job shown in FIG. 13 are executed similarly in the second embodiment. However, the control amount in the figure is the control amount of the rotational speed of the drive motor M2 of the secondary transfer roller 36.

  According to the control of the second embodiment, by changing the rotation speed of the secondary transfer roller 36, the length in the conveyance direction of the image formed on the recording material can be set regardless of the change in the friction coefficient μs1 of the intermediate transfer belt. Obtained stably.

  When changing the rotation speed of the secondary transfer roller 36, the drive motor M1 may be controlled so that the relative speed between the intermediate transfer belt 31 and the secondary transfer roller 36 is not changed. In this case, the image expansion / contraction performed in the secondary transfer portion T2 is executed by being transferred to the primary transfer portion Ta (Tb, Tc, Td). A toner image formed uniformly on the photosensitive drum 11a (11b, 11c, 11d) is stretched and carried on the intermediate transfer belt 31.

<Example 3>
As shown in FIG. 2, a registration roller 25 is provided upstream of the secondary transfer portion T2 formed by the intermediate transfer belt 31 and the secondary transfer roller 36, and the recording material P is supplied to the secondary transfer portion T2. .

  The moving speed of the intermediate transfer belt 31 passing through the secondary transfer portion T2 is V1, and the rotation speed of the registration roller 25 is V2. In Embodiment 3, in order to prevent a shock that occurs at the moment when the trailing edge of the recording material P passes through the registration roller 25, the recording material P is in contact with the secondary transfer portion T2 and the registration roller 25. V2 ≧ V1.

  In addition, if the conveyance force of the registration roller 25 becomes unstable, an unstable image may be caused as well as an image defect. In the third embodiment, the conveyance force of the registration roller 25 is secondary. It is set larger than the conveying force of the transfer portion T2.

  Also in the case of the image forming apparatus 100 configured as described above and having the friction coefficient μs1 of the intermediate transfer belt 31 larger than that of the secondary transfer roller 36, the same control as in the first and second embodiments is applied. it can.

  In Embodiment 3, the image formed on the recording material is adjusted by adjusting the scanning speed of the exposure device 13a (13b, 13c, 13d) and the rotational speed of the secondary transfer roller 36 according to the glossiness of the intermediate transfer belt 31. The length in the transport direction can be stabilized.

<Example 4>
As shown in FIG. 2, in the fourth embodiment, the control amount of the image expansion / contraction magnification is changed based on the output of the temperature / humidity sensor 65. This is because the friction coefficient μs1 on the surfaces of the intermediate transfer belt 31 and the secondary transfer roller 36 also changes depending on the temperature and humidity, and affects the length in the conveyance direction of the image formed on the recording material.

  For example, the friction coefficient of the intermediate transfer belt 31 and the secondary transfer roller 36 in the image forming apparatus 100 according to the first embodiment changes according to temperature and humidity as shown in Table 2. This is because the release layers of the intermediate transfer belt 31 and the secondary transfer roller 36 each have a slight moisture absorption characteristic, and the surface becomes tacky as the amount of moisture absorption increases, increasing the frictional forces μs1 and μs2.

  Accordingly, when the temperature and humidity change, the recording material holding and conveying force in the secondary transfer portion T2 varies, and the length of the image formed on the recording material in the conveying direction varies.

  In the fourth embodiment, the scanning speed of the exposure device 13a or the rotation speed of the secondary transfer roller 36 is changed according to the measurement result of the glossiness of the intermediate transfer belt 31 and the output of the temperature / humidity sensor 65 at that time. It was. As a result, the length of the image formed on the recording material in the conveyance direction is stable even under different temperature and humidity conditions.

Second Embodiment
FIG. 15 is an explanatory diagram of a configuration of the image forming apparatus according to the second embodiment.

  The present invention is not limited to a tandem type image forming apparatus in which a plurality of photosensitive drums are arranged along an intermediate transfer belt, but also a one-drum type image that primarily transfers a plurality of color toner images from one photosensitive drum to an intermediate transfer member. It can also be implemented with a forming apparatus.

  As shown in FIG. 15, in the image forming apparatus 200 of the second embodiment, the photosensitive drum 11 including a plurality of developing devices 14a, 14b, 14c, and 14d is disposed in contact with the intermediate transfer drum 31D. .

  First, the electrostatic image formed on the photosensitive drum 11 by the exposure device 13 is developed by the developing device 14a to form a yellow toner image, and is primarily transferred to the intermediate transfer drum 31D at the primary transfer portion T1.

  Next, the electrostatic image formed on the photosensitive drum 11 is developed by the developing device 14b to form a magenta toner image, and is primary-transferred to the intermediate transfer drum 31D so as to overlap the yellow toner image at the primary transfer portion T1. .

  Next, the electrostatic image formed on the photosensitive drum 11 is developed by the developing device 14c to form a cyan toner image, and is primary-transferred to the intermediate transfer drum 31D so as to overlap the magenta toner image at the primary transfer portion T1. .

  Finally, the electrostatic image formed on the photosensitive drum 11 is developed by the developing device 14d to form a black toner image, and is primarily transferred to the intermediate transfer drum 31D so as to overlap the cyan toner image at the primary transfer portion T1. .

  The four-color toner images primarily transferred to the intermediate transfer drum 31D are transported to the secondary transfer portion T2, and are collectively transferred to the recording material P, and are subjected to heat and pressure by the fixing device 40 to receive the recording material P. A toner image is fixed on the surface.

  The secondary transfer roller 36 is in pressure contact with the intermediate transfer drum 31D to form a secondary transfer portion T2 that is an example of a transfer portion.

  The cleaning device 19 rubs and removes the transfer residual toner on the intermediate transfer drum 31D that has passed through the secondary transfer portion T2 without being secondarily transferred to the recording material P, by a cleaning blade.

  Also in the image forming apparatus 200 configured as described above, the glossiness of the intermediate transfer drum 31D can be measured based on the output of the optical sensor 60 as in the first embodiment. Then, by adjusting the scanning speed of the exposure device 13 according to the measurement result of the glossiness, the length of the toner image transferred in the secondary transfer portion T2 in the transport direction can be adjusted.

It is explanatory drawing of a structure of the image forming apparatus of 1st Embodiment. It is explanatory drawing of a structure of an image formation part and a secondary transfer part. FIG. 6 is an explanatory diagram of a configuration of an intermediate transfer belt. It is explanatory drawing of a structure of a secondary transfer roller. It is explanatory drawing of resistance measurement of a secondary transfer roller. It is explanatory drawing of the frictional force which acts on the recording material which passes a secondary transfer part. It is explanatory drawing of the image for a measurement used in order to measure the length of the conveyance direction of an output image. It is explanatory drawing of the measurement of the static friction coefficient of an intermediate transfer belt. FIG. 6 is an explanatory diagram of a relationship between the cumulative number of image formations and the glossiness of an intermediate transfer belt. FIG. 6 is an explanatory diagram of a relationship between glossiness of an intermediate transfer belt and image magnification. It is explanatory drawing of a structure of an optical sensor. FIG. 6 is an explanatory diagram of a relationship between glossiness of an intermediate transfer belt and an output of an optical sensor. It is a flowchart of initialization control. 6 is a flowchart of image magnification adjustment control for each job. It is explanatory drawing of a structure of the image forming apparatus of 2nd Embodiment.

Explanation of symbols

11a, 11b, 11c, 11d Image carrier (photosensitive drum)
13a, M2 adjusting means (exposure device, drive motor)
31 Intermediate transfer member (intermediate transfer belt)
312 Elastic layer 36 Transfer rotator (secondary transfer roller)
364 Release layer (coat layer)
40 Fixing means (fixing device)
60 Glossiness detection means, reflected light detection means (optical sensor)
65 Detection means (temperature / humidity sensor)
80 Control means (control unit)
81 Input means (operation panel)
82 Storage Device 100 Image Forming Device 100R Measuring Means (Image Reading Device)
D2 Power supply means (power supply)
GA measurement image P Recording material T2 Transfer part (secondary transfer part)

Claims (6)

A rotatable photoreceptor,
Exposure means for forming an electrostatic image on the charged photoreceptor;
Developing means for attaching a toner to the electrostatic image formed on the photoreceptor to form a toner image;
An intermediate transfer member having an elastic layer to which the toner image of the photosensitive member is transferred;
Intermediate transfer body driving means for rotationally driving the intermediate transfer body;
The toner image on the intermediate transfer member is electrostatically transferred to the recording material while being held while being conveyed by being pressed toward the intermediate transfer member, and is rotatable with a release layer on the surface. A transfer roller;
An image forming apparatus comprising: a transfer roller driving unit that rotationally drives the transfer roller;
Glossiness detecting means for detecting the glossiness of the surface of the intermediate transfer member;
The length of the toner image on the intermediate transfer body in the rotational direction of the intermediate transfer body with respect to the same electrostatic image is changed according to the detection result of the glossiness of the surface of the intermediate transfer body by the glossiness detecting means. As described above , when the glossiness detection result is the first glossiness, the scanning line interval in the rotation direction of the photoconductor of the electrostatic image formed on the photoconductor is set as the glossiness detection result. a scanning line interval setting means for setting wider than the scanning line interval when the first higher gloss second glossiness, image forming apparatus characterized by Ru with a. An image carrier on which a toner image is formed;
An intermediate transfer member having an elastic layer to which a toner image of the image carrier is transferred;
Intermediate transfer body driving means for rotationally driving the intermediate transfer body;
The toner image on the intermediate transfer member is electrostatically transferred to the recording material while being held while being conveyed by being pressed toward the intermediate transfer member, and is rotatable with a release layer on the surface. A transfer roller;
An image forming apparatus comprising: a transfer roller driving unit that rotationally drives the transfer roller;
Glossiness detecting means for detecting the glossiness of the surface of the intermediate transfer member;
When the glossiness detection result of the surface of the intermediate transfer member by the glossiness detection means is the first glossiness, the driving speed of the transfer roller driving means is determined, and the glossiness detection result is the first glossiness. an image forming apparatus comprising a driving speed setting means for setting faster than a second, higher the driving speed when the glossiness, that Ru comprising a. A temperature / humidity sensor for detecting temperature / humidity in the image forming apparatus;
When the detection result of the temperature and humidity in the image forming apparatus of the temperature and humidity sensor is the first temperature and humidity, the scanning line interval in the rotation direction of the photosensitive member of the electrostatic image formed on the photosensitive member is set to the temperature and humidity. 2. The image forming apparatus according to claim 1, further comprising: a scanning line interval setting unit configured to set the detection temperature wider than the scanning line interval of the second temperature and humidity higher than that when the first temperature and humidity are set. . A temperature / humidity sensor for detecting temperature / humidity in the image forming apparatus;
When the temperature / humidity detection result in the image forming apparatus of the temperature / humidity sensor is the first temperature / humidity, the driving speed of the transfer roller driving means is set to be higher than the first temperature / humidity. The image forming apparatus according to claim 2, further comprising: a driving speed setting unit that sets the driving speed faster than the driving speed at a temperature and humidity of 2. It further comprises measuring means for measuring the length of the output image of the recording material in the conveying direction,
The image interval setting unit is configured to measure a measurement result of the length of the output image of the recording material in the conveying direction by the measuring unit in an initial state of the intermediate transfer member and a glossiness of the surface of the intermediate transfer member by the glossiness detecting unit. detection result based image forming apparatus according to claim 1 or 3, characterized in that the initial value of the rotational direction of the scanning line interval of said photosensitive member. It further comprises measuring means for measuring the length of the output image of the recording material in the conveying direction,
The drive speed setting unit is configured to measure the measurement result of the length of the output image of the recording material in the conveying direction in the initial state of the intermediate transfer member and the glossiness of the surface of the intermediate transfer member by the glossiness detection unit. The image forming apparatus according to claim 2 , wherein an initial value of a driving speed of the transfer roller driving unit is set based on a detection result .

Images