JP2004029304A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device which forms an image under the optimum image formation conditions corresponding to a transfer material. <P>SOLUTION: As a representative constitution, the image forming device is characterized in that: test printing is carried out while a condition changing means changes the image formation conditions; a read means reads the test print; a judging means judges the optimum image formation conditions for the transfer material; the judged image formation conditions are recorded in a recording means by kinds of transfer materials; a selecting means selects a transfer material in subsequent image formation; and image formation is carried out by using image formation conditions recorded in the recording means for the transfer material. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus capable of setting optimum image forming conditions according to a transfer material.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine, a printer, and a facsimile, various types of transfer materials are used, and the types of transfer materials required are increasing in recent years. These transfer materials have various characteristics such as thickness, electric resistance value, paper stiffness, and the like, and the optimum value of the image forming conditions differs depending on the transfer material. However, usually, in an image forming apparatus, image forming conditions use a fixed value irrespective of a transfer material, or have several modes such as "thick paper", "thin paper", and "recycled paper", each of which has a fixed value. It is common for the user to choose from these. Further, a method and a configuration in which the thickness, resistance, and the like of a transfer material are measured by a sensor and image forming conditions are determined in accordance with the measurement are known and are in practical use.
[0003]
[Problems to be solved by the invention]
However, if a constant value is provided for the image forming conditions irrespective of the transfer material, it is not possible to form an image under optimum conditions due to differences in the characteristics of the transfer material. Therefore, for example, in the case of thin paper, the transfer current becomes excessive, abnormal discharge occurs, and the image is disturbed, or an offset image is generated by applying excessive heat to the transfer material in the fixing device. Also, in the case of thick paper, insufficient transfer cannot be performed due to insufficient transfer current, resulting in transfer failure, or insufficient heat applied to the transfer material by the fixing device, and insufficient fixing of toner could not be performed. May occur.
[0004]
Further, since there are various types of transfer materials, it is difficult to handle all of them even when there are some modes, and the usability becomes extremely poor when there are too many modes. Further, even if the transfer material is divided by the thickness such as "thick paper" and "thin paper", the optimum conditions are not the same even if the thickness is the same because the characteristics of the transfer material are not determined by the thickness alone. Also, when using sensors, it is difficult to measure everything because the properties of paper are determined by numerous factors such as thickness, paper stiffness, electrical resistance, moisture content, surface properties, etc. However, when measured, there is a problem that it is not always possible to select the optimal condition when each factor has a correlation.
[0005]
Accordingly, it is an object of the present invention to provide an image forming apparatus capable of forming an image under an optimum image forming condition according to a transfer material.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, a typical configuration of an image forming apparatus according to the present invention includes an image carrier, a developing unit that forms a toner image on the image carrier, and a toner image from the image carrier. In an image forming apparatus having a transfer unit for transferring to a transfer material, a separating unit for separating the transfer material from the image carrier, and a fixing unit for fixing the toner image by heating and pressing the transfer material, the image forming conditions are set as follows. Condition changing means for changing, reading means for reading an output image, judging means for judging an optimum image forming condition from image information read by the reading means, recording means for recording a plurality of image forming conditions, Selecting means for selecting image forming conditions, executing a test print while changing the image forming conditions by the condition changing means, and reading the test print by the reading means The determination means determines an optimum image forming condition for the transfer material, and causes the recording means to record the determined image formation condition for each type of transfer material. By selecting, image formation is performed on the transfer material using the image forming conditions recorded in the recording unit.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
[First embodiment]
A first embodiment of the image forming apparatus according to the present invention will be described. FIG. 1 is a schematic configuration diagram of an image forming apparatus according to the present embodiment, and FIG. 2 is a graph showing a relationship between a transfer current for determining an optimum transfer current and luminance data.
[0008]
First, the overall configuration of the image forming apparatus will be described with reference to FIG. At the center of the image forming apparatus, a photosensitive drum 1 as an image carrier is provided rotatably in the direction of arrow R1. Around the photosensitive drum 1, a primary charger 2 for uniformly charging the surface of the photosensitive drum 1 along a rotation direction thereof, a latent image forming unit 20 for irradiating a laser beam L for exposure, and a developing device. A developing unit 3 having a developing sleeve 3a as a unit, a transfer charger 4 as a transfer unit for transferring a toner image formed on the photosensitive drum 1 to a transfer material P, and a cleaner 11 for removing residual toner An exposure lamp 10 for performing pre-exposure is provided. The transfer charger 4 is provided with a cleaner 41 for the transfer charger.
[0009]
In this embodiment, the electrostatic latent image is visualized by reversal development. That is, the surface of the photosensitive drum 1 is uniformly charged to, for example, minus (-) by the primary charger 2, and an electrostatic latent image is formed by exposure of a semiconductor laser or the like which is turned on in response to an image signal. This electrostatic latent image is developed with a negatively charged developer, which is coated on the developing sleeve 3a of the developing device 3, to form a toner image.
[0010]
Next, the toner image on the photosensitive drum 1 is transferred to the transfer material P by the transfer charger 4. The transfer material P is conveyed from the feed cassette 22 to the registration roller 5 via a feed roller or the like, and further uniformly adhered to the photosensitive drum 1 by the transfer guide 6. The toner image is transferred to the transfer material P. At this time, the transfer material P is given a charge of the opposite polarity (positive) to the back surface of the transfer material P by corona discharge, so that the toner on the photosensitive drum 1 is strongly attracted to the transfer material P electrically. Is transcribed.
[0011]
The transfer material P to which the toner image has been transferred is separated from the photoreceptor drum 1 by removing the remaining charge on the back surface thereof by the separation charge removing needle charger 7. The separated transfer material P is transported along the guide member 8 and delivered to the transfer material transport unit 9. Thereafter, the transfer material P is fixed on the toner image by the fixing device 16, is conveyed along the fixing discharge guide member 53, is transferred to the transfer material discharge unit 54, and is discharged outside the apparatus.
[0012]
In the above-described image formation, pre-exposure is performed by the exposure lamp 10, and removal and collection of residual toner on the photosensitive drum 1 are performed by the cleaner 11.
[0013]
Further, an image reading means 51 using a CCD (Charge Coupled Device) or the like is provided above the transfer material transport unit 9 so that a toner image on the transfer material P passing through the transfer material transport unit 9 can be read. Has become.
[0014]
(Storage and selection of image forming conditions)
In this embodiment, the transfer current setting mode is executed for a transfer material that is likely to be used frequently. First, the user inputs the name of the transfer material from an operation unit and a display unit (not shown). The data is recorded in an optimum current value recording means (not shown).
[0015]
Next, a test print is performed. The test print uses a transfer material to be used, and automatically outputs, for example, 11 images of a solid black image from 600 μA to 600 μA by increasing the transfer current from 400 μA to 20 μA per sheet. This is read by the image reading means 51, decomposed into a number of pixels, and luminance data having a linear characteristic with respect to the amount of reflected light is obtained. When the transfer current is insufficient, a transfer failure occurs, so that the density becomes low, and the brightness data obtained therefrom has a large value. Therefore, it can be said that the smaller the total luminance data of the obtained image is, the less the occurrence of transfer failure and the better the image is formed. However, if the transfer current is too large, an abnormal discharge is generated from the transfer charger 4 to the drum, and the abnormal discharge may disturb the image, that is, a so-called leak image may occur. Therefore, if the transfer current is too small, transfer failure occurs, and if it is too large, a leak image occurs.
[0016]
In the present embodiment, an optimum transfer current value is calculated by a transfer current optimum value calculation device (judging means) not shown. The calculation method can be obtained by writing a graph as shown in FIG. 2 from the transfer current and the luminance data. In FIG. 2, the vertical axis represents the sum of the luminance data, and the horizontal axis represents the transfer current value. When the transfer current is insufficient, a transfer failure occurs, so that the sum of the luminance data becomes a large value. As the transfer current increases, the occurrence of transfer failures decreases, so that the sum of the luminance data decreases. Since the transfer failure does not occur if the transfer current exceeds the required transfer current, the transfer current saturates at the transfer current A as luminance data. Since this transfer current A is the minimum transfer current value at which no transfer failure occurs, A + 20 μA with a margin of 20 μA added thereto is determined as the optimum transfer current.
[0017]
The optimum transfer current value for the transfer material obtained in this way is recorded in the optimum current value recording means together with the name of the transfer material recorded first, and the transfer current setting mode ends. The name of the recorded transfer material is displayed on the display unit, and by making it selectable, the transfer current optimum value recorded together with the name of the transfer material is set for the subsequent image output. Has become.
[0018]
Therefore, when the user uses a transfer material for which the transfer current value setting mode has already been executed, the user simply selects the name of the transfer material from a display unit (not shown), and the optimum transfer current for the transfer material is selected. Is selected, and high-quality output without occurrence of transfer failure or leak image can be achieved. The same operation is performed for all frequently used transfer materials, and the name of the transfer material and the optimum transfer current value are recorded together. Thereafter, before the image is output, the name of the transfer material to be used is changed. Just by selecting, the optimum transfer current value is selected, and high image quality output is possible.
[0019]
In the above embodiment, the recording means specifically uses a rewritable ROM or a hard disk provided inside the apparatus, and stores the optimum value even when the apparatus is turned off. The transfer current optimum value calculation device serving as the determination means may also be used as a CPU for controlling the image forming apparatus, or may be provided with an independent controller chip.
[0020]
As described above, for the transfer material to be used for the first time, using the transfer material in advance, performing a test print while changing the image forming conditions, obtaining the image information by the output image reading means, and obtaining the image information from the actual output image. By automatically determining the optimum image forming conditions to be obtained and registering (recording) the optimum conditions together with the name of the transfer material, when the transfer material is used thereafter, the registered name is used. By simply performing the image formation after the selection, the optimum image formation conditions for the transfer material are selected, so that high-quality output is possible.
[0021]
Further, by setting the image forming condition to the transfer current, the output can be performed under the optimum transfer current condition, so that it is possible to prevent problems such as transfer failure and abnormal discharge image caused by excessive or insufficient transfer current. .
[0022]
[Second embodiment]
A second embodiment of the image forming apparatus according to the present invention will be described. FIG. 3 is a graph showing the relationship between the separation current and the luminance data for determining the optimum separation current. Parts that are the same as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. . In the first embodiment, the transfer current setting mode in which the transfer current is stored and selectable for the transfer material that is likely to be used frequently is described. In the present embodiment, the same setting mode is used for the separation current. Execute.
[0023]
First, similarly to the first embodiment, the user first inputs the name of the transfer material from an operation unit and a display unit (not shown). The data is recorded in an optimum current value recording means (not shown).
[0024]
Next, a test print is performed. In the test printing, a transfer material to be used is used, and the separation current is increased from -800 μA by 50 μA for each sheet, and 16 sheets are output to −50 μA. If the separation current is insufficient, a paper jam may occur depending on the transfer material. Therefore, the separation current is changed from the one having a larger absolute value (excessive separation current). Further, when a paper jam occurs, it is clear that a separation failure due to a shortage of the separation current has occurred at that point, so that test printing in which the absolute value of the transfer current is further reduced is not performed. This test print is read by the image reading means 51 and decomposed into a large number of pixels to obtain luminance data having a linear characteristic with respect to the amount of reflected light.
[0025]
When the separation current is excessive, so-called retransfer occurs. Retransfer means that when the separation current is excessive, the charge on the back surface of the transfer material (charge of the opposite polarity to the toner image) becomes too small when the transfer material is separated, and the electrostatic charge between the transfer material and the surface of the image carrier is reduced. However, the transfer material can be separated, but the force of the charge on the back surface of the transfer material to hold the toner image on the transfer material is too weak. Therefore, at the moment the transfer material separates from the surface of the image carrier, the toner image once transferred to the transfer material is attracted again to the electrostatic latent image formed on the surface of the image carrier, is taken away, and the image is lost. Or decrease in concentration.
[0026]
Even when the separation current is insufficient, the separation from the photoconductor drum is not sufficiently performed, so that the photoconductor drum sticks to the photoconductor drum even after passing through the separation unit or moves along the photoconductor drum. As a result, the time during which the separation current acts on the transfer material is prolonged, and the application of the separation current to the transfer material becomes excessive, so that the toner image once supposed to be transferred to the transfer material is again formed on the surface of the image carrier. Re-transfer occurs. Further, if the separation current is insufficient, the separation from the photosensitive drum cannot be performed at all, and the sheet sticks to the photosensitive drum and enters the cleaning section of the photosensitive drum to cause a paper jam or a drum separation claw. In this case, the transfer member is forcibly separated from the photosensitive drum by the claw, but the tip of the transfer material may be stained by contact with the claw portion.
[0027]
In the present embodiment, the image reading unit 51 reads the image, decomposes it into a large number of pixels, and obtains luminance data having a linear characteristic with respect to the amount of reflected light. I can judge. If the separation current is excessive, retransfer occurs, and image dropout or density drop occurs, so that the image density becomes low and the brightness data obtained therefrom has a large value. Similarly, when the separation current is insufficient, retransfer occurs, and image dropout or density drop occurs, so that the image density decreases and the brightness data obtained therefrom has a large value. Further, if the separation current is insufficient, paper jam occurs. Therefore, it can be said that the smaller the total luminance data of the obtained image is, the less re-transfer occurs and the better the image is formed.
[0028]
In the present embodiment, an optimum separation current value is calculated by a separation current optimum value calculation device (judging means) not shown. The calculation method can be obtained by writing a graph as shown in FIG. 3 from the separation current and the luminance data. In FIG. 3, the vertical axis represents the sum of the luminance data, and the horizontal axis represents the transfer current value. If the separation current is excessive, retransfer occurs, so that the sum of the luminance data becomes a large value. As the absolute value of the separation current decreases, the occurrence of retransfer decreases, so that the sum of the luminance data decreases. When the separation current is B, the sum of the luminance data becomes minimum. When the absolute value of the separation current is further reduced, the separation current becomes excessive, retransfer occurs more frequently, and the sum of the luminance data increases. When the separation current is further reduced, paper jam occurs. If a paper jam occurs, do not perform any further test printing. It is determined that the separation current B obtained in this manner is the optimum separation current for the transfer material that causes the least retransfer.
[0029]
The optimum separation current value of the transfer material obtained in this way is recorded in the optimum current value recording means together with the name of the transfer material recorded first, and the separation current setting mode ends. The name of the recorded transfer material is displayed on the display unit, and by selecting it, the optimal separation current value recorded together with the name of the transfer material is set for the image output performed thereafter. I have.
[0030]
Therefore, when the user subsequently uses the transfer material for which the separation current setting mode has been executed, the user simply selects the name of the transfer material on the display unit, and the optimum separation current value for the transfer material is selected. Thus, high-quality output without retransfer is possible. The same operation is performed for all the frequently used transfer materials, and the name of the transfer material and the optimum separation current value are recorded together, so that the name of the transfer material to be used is thereafter changed before image output. Just by selecting, the optimum separation current value is selected, and high image quality output is possible.
[0031]
As described above, by setting the image forming condition to the separation current, the output can be performed under the optimum separation current condition. Therefore, it is possible to prevent the occurrence of problems such as retransfer and separation failure caused by excess or deficiency of the separation current. .
[0032]
[Third embodiment]
A third embodiment of the image forming apparatus according to the present invention will be described. FIG. 4 is a schematic configuration diagram of the image forming apparatus according to the present embodiment, and FIG. 5 is a graph showing the relationship between the adjusted temperature and the luminance data for determining the optimal adjusted temperature. The same reference numerals are given to the same parts in the description, and the description is omitted.
[0033]
As shown in FIG. 4, in the present embodiment, the fixing device 16 has a fixing roller 55 rotatably disposed as a fixing rotating body, and a pressure roller 56 that rotates while being pressed against the fixing roller 55. The configuration is as follows. In the present embodiment, the diameter of the fixing roller 55 is 30 mm (perimeter of about 94 mm), and the diameter of the pressure roller 56 is 20 mm (perimeter of about 63 mm). A heater 57 such as a halogen lamp is provided inside the fixing roller 55. Further, a thermistor 58 is provided so as to be in contact with the fixing roller 55, and by controlling the voltage to the heater 57 through a temperature control circuit, the surface temperature of the fixing roller 55 is maintained at an arbitrary temperature. Adjustments are made. The transfer material P has the toner image fixed thereon by the fixing device 16, is conveyed along the fixing / discharge guide member 53, is delivered to the transfer material discharge unit 54, and is discharged outside the apparatus. An image reading means 52 using a CCD (charge coupled device) or the like is provided above the fixing / discharging guide member 53 so that a toner image on a transfer material passing through the fixing / discharging guide member 53 can be read. .
[0034]
In the present embodiment, for a transfer material that is likely to be used frequently, a fixing temperature adjustment setting mode for storing and selecting the tone temperature of the fixing device 16 for the transfer material is executed. First, the user inputs the name of the transfer material from an operation unit and a display unit (not shown). The data is recorded in an optimum temperature control temperature recording means (not shown).
[0035]
Next, a test print is performed. The test print uses a transfer material to be used. For example, a solid black image from the front end of the transfer material in the traveling direction to a 20 mm portion and a solid white image from the rest are fixed at a fixing temperature of 140 ° C to 10 ° C for each sheet. 9 sheets are automatically output up to 220 ° C. The output image is read by the image reading means 52, decomposed into a number of pixels, and luminance data having a linear characteristic with respect to the amount of reflected light is obtained.
[0036]
When the fixing temperature control is insufficient, the toner image on the transfer material adheres to the fixing roller 55 during paper feeding due to insufficient softening and melting of the toner, and an offset is generated at a position corresponding to the peripheral length of the fixing roller. That is, a so-called low-temperature offset occurs. If the temperature is too high, the toner is completely melted, the cohesive force of the toner is reduced, and the toner image on the transfer material adheres to the fixing roller 55 during paper passing, which corresponds to the circumference of the fixing roller. A so-called high-temperature offset, which causes an offset at the position where the offset occurs, occurs. For example, when the diameter of the fixing roller 55 is 30 mm (peripheral length 94 mm), a low-temperature offset or a high-temperature offset occurs from a solid black image 20 mm from the leading end, so that an offset image is generated from 94 mm to 114 mm from the leading end. The level of the offset can be determined by measuring the luminance data of the portion where the offset occurs (94 mm to 114 mm from the leading end of the transfer material in this embodiment). When the level of the offset is poor, the offset toner image is present, so that the luminance data has a small value. The smaller the occurrence of the offset, the larger the sum of the luminance data at the measured location.
[0037]
In the present embodiment, an optimum temperature adjustment temperature is calculated by a fixing temperature adjustment optimum value calculation device (judging means) not shown. The calculation method can be obtained by writing a graph as shown in FIG. 5 from the adjusted temperature and the luminance data. In FIG. 5, the vertical axis represents the sum of the luminance data of the portion where the offset occurs (94 mm to 114 mm from the leading end of the paper in the present embodiment), and the horizontal axis represents the temperature regulation temperature. If the temperature control temperature is insufficient, a low-temperature offset occurs, so that the sum of the luminance data has a small value. When the temperature control temperature is increased, the occurrence of the low-temperature offset decreases, so that the sum of the brightness data decreases. When the temperature control temperature is C, the sum of the brightness data becomes maximum. If the temperature control temperature is further increased, the temperature control temperature becomes excessive, the occurrence of high-temperature offset increases, and the sum of the luminance data decreases. The temperature control temperature C obtained in this way is determined to be the optimum temperature control temperature for the transfer material, which causes the least occurrence of offset.
[0038]
The optimum temperature control temperature of the transfer material obtained in this way is recorded on the optimum temperature control temperature recording means together with the name of the transfer material recorded first, and the temperature control temperature setting mode ends. The name of the recorded transfer material is displayed on the display unit, and by selecting the selected name, the optimal temperature control temperature recorded together with the name of the transfer material is set for the image output performed thereafter. ing.
[0039]
Therefore, when the user uses a transfer material for which the temperature control temperature setting mode has already been executed, the user simply selects the name of the transfer material on the display unit, and the optimum temperature control temperature for the transfer material is determined. It is possible to output a high-quality image that is selected and does not generate an offset image. The same operation is performed for all frequently used transfer materials, and the name of the transfer material and the optimum temperature are recorded together, so that the name of the transfer material to be used can be changed before the image is output. Just by selecting, the optimum temperature is selected, and high-quality output is possible.
[0040]
As described above, by setting the image forming conditions to the fixing temperature control, the output can be performed under the optimum fixing temperature control conditions. It is possible to prevent the occurrence of problems such as lowering, shortening of the life of the fixing device due to thermal stress, and defective fixing.
[0041]
[Fourth embodiment]
A fourth embodiment of the image forming apparatus according to the present invention will be described. Portions that are the same as those in the above embodiments are given the same reference numerals, and descriptions thereof are omitted. In the first embodiment, the transfer current is used as the image forming condition, the separation current is used as the image forming condition in the second embodiment, and the fixing temperature is used as the image forming condition in the third embodiment. In the mode, the optimum image forming condition setting mode is executed using all of them as image forming conditions.
[0042]
First, the user inputs the name of the transfer material from the operation unit and the display unit. The data is recorded in an optimum image forming condition recording unit (not shown).
[0043]
Next, in the same manner as described in the first embodiment, the optimum transfer current is determined by test printing, and is recorded on the optimum image forming condition recording means together with the name of the transfer material. Similarly, in the same manner as described in the second and third embodiments, the optimum separation current value and the optimum fixing temperature control temperature are determined by test printing, and the optimum image forming condition recording means is combined with the name of the transfer material and the optimum transfer current value. Then, the optimum image forming condition setting mode is ended. The name of the recorded transfer material is displayed on the display unit, and by selecting it, the image output performed thereafter will have the optimal transfer current value, the optimal separation current value, and the optimal fixation recorded together with the name of the transfer material. A regulated temperature is set.
[0044]
Therefore, when the user uses a transfer material for which the optimum image forming condition setting mode has been executed, the user simply selects the name of the transfer material on the display unit, and the optimum transfer current value for the transfer material is used. , The optimum separation current value and the optimum fixing temperature are selected, and high-quality output without occurrence of transfer failure, leak image, retransfer, and fixing offset can be achieved. The same operation is performed for all the frequently used transfer materials, and the name of the transfer material and the optimum image forming conditions are recorded together. After that, before the image is output, the name of the transfer material to be used is changed. Just by selecting, the optimum image forming condition is selected, and high-quality output is possible.
[0045]
[Fifth embodiment]
A fifth embodiment of the image forming apparatus according to the present invention will be described with reference to the drawings. FIG. 6 is a diagram for explaining a correction table of the optimum image forming conditions according to the temperature and the humidity at the time of use. Parts that are the same as those in the above-described embodiments are denoted by the same reference numerals and description thereof is omitted. I do.
[0046]
In the present embodiment, a temperature sensor and a humidity sensor (not shown) are provided, and the temperature and the humidity at the time of image output can be measured. Since the optimum image forming condition changes depending on the temperature and humidity, the already recorded optimum image forming condition is corrected in accordance with the temperature and humidity at the time of image formation.
[0047]
First, as described in the fourth embodiment, when the optimum image forming condition setting mode is executed, the optimum image forming condition recording is performed by combining the name of the transfer material, the optimum image forming condition, and the temperature and humidity at that time. Record in the means. Thereafter, when the user uses a transfer material for which the optimum image forming condition setting mode has been executed, the user simply selects the name of the transfer material on the display unit, and the optimum transfer current value recorded for the transfer material is used. , The optimum separation current value, the optimum fixing temperature, and the temperature and humidity at the time of recording.
[0048]
Here, the current temperature and humidity are measured, and the optimum transfer current value, the optimum separation current value, and the optimum fixing temperature control temperature are determined based on the difference between the temperature and the humidity at the time of recording recorded in the optimal image forming condition recording means. Is corrected, and an image is formed using the corrected image, whereby a high-quality output without occurrence of transfer failure, leak image, retransfer, and fixing offset becomes possible.
[0049]
For example, when the temperature at the time of use is lower than the temperature at the time of executing the optimum image forming condition setting mode, the fixing roller 55 has a predetermined temperature because the temperature is controlled by the thermistor 58. Since the temperature of the roller 56 and the transfer material P is lower than when the optimum image forming condition setting mode is performed, a low-temperature offset easily occurs. Conversely, when the temperature at the time of use is higher than the temperature at the time of executing the optimum image forming condition setting mode, the fixing roller 55 has a predetermined temperature because the temperature is controlled by the thermistor 58. 56, since the temperature of the transfer material P is higher than when the optimum image forming condition setting mode is performed, a high-temperature offset easily occurs.
[0050]
Further, when the humidity at the time of use is different from the humidity at the time of executing the optimum image forming condition setting mode, the resistance of the paper, the stiffness of the paper, and the like change. Therefore, it is desirable to correct the transfer current and the separation current. .
[0051]
FIG. 6 shows an example of correction of the optimum image forming conditions according to the temperature and humidity during use. D, E, and F in FIG. 6 are transfer current values recorded when the optimum image forming condition setting mode is executed and corresponding to the temperature and humidity in the use environment of the apparatus when the optimum image forming condition setting mode is executed. , The separation current value and the temperature adjustment temperature.
[0052]
In the present embodiment, the optimum transfer current value and the optimum separation current value are corrected according to the humidity at the time of use, and the optimum fixing temperature control temperature is corrected according to the temperature. Specifically, when the humidity is low, the transfer current is set high and the separation current is set low. When the humidity is high, the transfer current is set low and the separation current is set high. When the temperature is low, the controlled temperature is set high, and when the temperature is high, the controlled temperature is set low. Based on such a criterion, the optimum transfer current value, the optimum separation current value, and the optimum fixing temperature for the transfer material are corrected.
[0053]
The same operation is performed for all frequently used transfer materials, and the names of the transfer materials, the optimal image forming conditions, the temperature, and the humidity are recorded together. Only by selecting the name of the material, the optimum image forming conditions in consideration of the temperature and humidity at the time of output are selected, and high-quality output is possible.
[0054]
In FIG. 6, the temperature difference and the humidity difference to be corrected and the degree to which each optimum value is corrected can be appropriately set according to the device configuration and the installation location, and the present invention is not limited to the exemplified numerical values. Absent.
[0055]
【The invention's effect】
As described above, the image forming apparatus according to the present invention performs a test print for a transfer material to be used for the first time while changing the image forming conditions using the transfer material in advance, and outputs the test print to the image information by the output image reading unit. , Automatically determine the optimal image forming conditions obtained from the actual output image, and register (record) the optimal conditions along with the name of the transfer material, and then use that transfer material In this case, simply selecting the registered name and then forming an image will select the optimum image forming conditions for the transfer material, so that defective images such as transfer failure, leak image, retransfer, and fixing offset will occur. It is possible to output with high image quality without generation of image.
[0056]
In addition, since the image is output at the optimum current value and the controlled temperature, unnecessary power is not used, so that the energy consumption efficiency is high, and it is possible to prevent excessive electrical and thermal stress. As a result, a high durability life of the device can be achieved.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment.
FIG. 2 is a graph showing a relationship between a transfer current and luminance data for determining an optimum transfer current.
FIG. 3 is a graph showing a relationship between a separation current and luminance data for determining an optimum separation current.
FIG. 4 is a schematic configuration diagram of an image forming apparatus according to a third embodiment.
FIG. 5 is a graph showing a relationship between a temperature control temperature and luminance data for determining an optimum temperature control temperature.
FIG. 6 is a diagram illustrating a correction table of optimal image forming conditions according to temperature and humidity during use.
[Explanation of symbols]
L: Laser beam
P: Transfer material
1. Photosensitive drum
2 Primary charger
3. Developing device
3a: Developing sleeve
4 ... transfer charger
5… Registration roller
6… Transfer guide
7 Separation static elimination needle charger
8 ... guide member
9… Transfer material transport section
10 Exposure lamp
11 ... cleaner
16 ... Fixing unit
20 ... latent image forming means
22… feed cassette
41 ... cleaner for transfer charger
51 image reading means
52 image reading means
53… Fixing discharge guide member
54: Transfer material discharge section
55 ... fixing roller
56… Pressure roller
57… heater
58… Thermistor

Claims (8)

An image carrier, a developing device for forming a toner image on the image carrier, a transfer device for transferring the toner image from the image carrier to a transfer material, and a separating device for separating the transfer material from the image carrier. A fixing unit for fixing the toner image by heating and pressing the transfer material,
Condition changing means for changing image forming conditions;
Reading means for reading an output image;
Determining means for determining an optimal image forming condition from the image information read by the reading means;
Recording means for recording a plurality of image forming conditions;
Selecting means for selecting the recorded image forming conditions,
Performing a test print while changing the image forming conditions by the condition changing means,
Reading a test print by the reading means,
The optimal image forming conditions for the transfer material are determined by the determining unit,
Causing the recording means to record the determined image forming conditions for each type of transfer material,
In the following image forming, an image forming apparatus is characterized in that by selecting a transfer material by the selecting means, an image is formed on the transfer material using image forming conditions recorded in the recording means. The image forming apparatus according to claim 1, wherein the image forming condition includes a transfer condition. The image forming apparatus according to claim 2, wherein the transfer condition is a transfer current. The image forming apparatus according to claim 1, wherein the image forming condition includes a separation condition. The image forming apparatus according to claim 4, wherein the separation condition is a separation current. The image forming apparatus according to claim 1, wherein the image forming condition includes a fixing condition. The image forming apparatus according to claim 4, wherein the fixing condition is a fixing temperature control. The image forming apparatus has a temperature detecting unit and a humidity detecting unit,
The recording unit records the temperature and the humidity together with the image forming conditions,
2. The image forming apparatus according to claim 1, wherein in the subsequent image forming, the image forming is performed by correcting the recorded image forming conditions according to a difference between the temperature and the humidity at the time of image forming and the recorded temperature and humidity. Image forming apparatus.

Images