Image forming apparatus with control part that corrects potential difference based on temperature difference
View Patent ↗An image forming apparatus includes a development part, a temperature detection part that detects an apparatus inner temperature, and a control part that corrects a potential difference (ΔV) between the development voltage and the supply voltage based on a temperature difference (ΔT). The potential difference is an absolute value determined by follow: Δ V =|(the development voltage)−(the supply voltage).| the temperature difference is determined by follow: Δ T =(the apparatus inner temperature)−(a glass transition starting temperature). The glass transition starting temperature is determined in consideration of a differential scanning calorimetry (DSC) curve of the toner.
1. An image forming apparatus, comprising:
a development part that includes
a developer carrier to which a development voltage (V 1 ) is applied and
a supply member to which a supply voltage (V 2 ) is applied, the supply member supplying toner on a surface of the developer carrier;
a temperature detection part that detects an apparatus inner temperature that is measured inside or near the developer carrier; and
a control part that corrects a potential difference (ΔV) between the development voltage and the supply voltage based on a temperature difference (ΔT), wherein
the potential difference is an absolute value determined by:
Δ V =|(the development voltage)−(the supply voltage)|
the temperature difference is determined by:
Δ T =(the apparatus inner temperature)−(a glass transition starting temperature),
the glass transition starting temperature is defined as a temperature corresponding to an intersection between a base line and a glass transition start judgment tangent line, which are specified based on a differential curve of a differential scanning calorimetry (DSC) curve of the toner measured using a DSC method, herein
the horizontal axis of the DSC curve: temperature (° C.),
the vertical axis of the DSC curve: calorific differential value (μW/° C.),
the base line is a line along an initial section of the DSC curve in which the calorific differential value is approximately constant with respect to the calorific differential value,
the glass transition start judgment tangent line is a tangent line which is in contact with the differential curve at an intersection between the differential curve and a glass transition start judgment line that is a line of which the calorific differential values are 1.5 times greater than those of the base line.
2. The image forming apparatus according to claim 1 , further comprising:
a development voltage control part that applies the development voltage to the developer carrier; and
a supply voltage control part that applies the supply voltage to the supply member.
3. The image forming apparatus according to claim 1 , wherein
the control part includes a temperature difference calculation part that calculates the temperature difference.
4. The image forming apparatus according to claim 3 , wherein
the control part includes a first coefficient determination part that determines a first correction coefficient (C 1 ) based on the temperature difference.
5. The image forming apparatus according to claim 4 , wherein
the control part includes a correction amount determination part that determines a correction amount (VR) to correct the potential difference based on the first correction coefficient.
6. The image forming apparatus according to claim 5 , wherein
the control part includes a potential difference correction part that corrects the potential difference based on the correction amount.
7. The image forming apparatus according to claim 6 , wherein
the control part further includes
a frequency measure part that measures a frequency indicating how many times images have been formed using the toner, and
a second coefficient determination part that determine a second correction coefficient (C 2 ) based on the frequency, wherein
the control part determines the correction amount based on the second correction coefficient in addition to the first correction coefficient.
8. The image forming apparatus according to claim 6 , wherein
the control part further includes
a dot number measure part that measures the dot number associated with formation of an image using the toner,
a print rate calculation part that calculates a print rate based on the dot number, and
a third coefficient determination part that determines a third correction coefficient (C 3 ) based on the print rate, wherein
the control part determines the correction amount based on the third correction coefficient in addition to the first correction coefficient.
9. The image forming apparatus according to claim 6 , wherein
the control part further includes
a frequency measure part that measures a frequency indicating how many times images have been formed using the toner, and
a second coefficient determination part that determine a second correction coefficient (C 2 ) based on the frequency,
a dot number measure part that measures the dot number associated with formation of an image using the toner,
a print rate calculation part that calculates a print rate based on the dot number, and
a third coefficient determination part that determines a third correction coefficient (C 3 ) based on the print rate, and
the control part determines the correction amount based on the second correction coefficient and the third correction coefficient in addition to the first correction coefficient.
10. The image forming apparatus according to claim 5 , further comprising:
an editing memory that stores a coefficient table for determining the first correction coefficient in which the temperature difference is segmented by several groups, one of which is zero or less, the remaining of which are more than zero, and each of the groups including the first correction coefficient,
in case where the temperature difference is zero or less, the correction coefficient is substantially constant regardless of an amount of the temperature difference,
in case where the temperature difference is more than zero, the correction coefficient increases as the temperature difference increases.
11. The image forming apparatus according to claim 3 , wherein
the control part causes the development voltage control part to increase the development voltage applied to the developer member by the correction amount such that the potential difference becomes smaller.
12. The image forming apparatus according to claim 3 , wherein
the control part causes the supply voltage control part to decrease the development voltage applied to the supply member by the correction amount such that the potential difference becomes smaller.
13. The image forming apparatus according to claim 1 , further comprising
a transfer part that transfers the toner to a medium, wherein
the apparatus inner temperature is a temperature of the transfer part.
14. The image forming apparatus according to claim 1 , wherein
the apparatus inner temperature is a temperature of the developer carrier.
15. The image forming apparatus according to claim 1 , wherein
the apparatus inner temperature is a temperature that is measured inside the development part.
16. The image forming apparatus according to claim 1 , wherein
the control part further includes
a time measure part that measures an elapsed time that is determined after a formation of the image using the toner begins, and
a time judgment part that judges whether or not the elapsed time has reached a target time, wherein
the control part corrects the potential difference when the elapsed time has reached the target time.