Abstract: An image forming apparatus includes a photoconductor, a power supply, and circuitry. The power supply is configured to apply a charging voltage to the photoconductor. The circuitry is configured to control film thickness detection of detecting a charging current corresponding to the charging voltage to detect a film thickness of a surface of the photoconductor. The circuitry is further configured to determine a sampling period taken to detect the charging current; calculate a variation in the charging current detected; and determine whether the variation is greater than a threshold. The circuitry is configured to: determine the sampling period according to a determination result as to whether the variation is greater than the threshold; and sample the charging current for the sampling period determined, on a subsequent film thickness detection control.

Abstract: An image forming apparatus includes a photoconductor, a power supply, and circuitry. The power supply is configured to apply a charging voltage to the photoconductor. The circuitry is configured to control film thickness detection of detecting a charging current corresponding to the charging voltage to detect a film thickness of a surface of the photoconductor. The circuitry is further configured to determine a sampling period taken to detect the charging current; calculate a variation in the charging current detected; and determine whether the variation is greater than a threshold. The circuitry is configured to: determine the sampling period according to a determination result as to whether the variation is greater than the threshold; and sample the charging current for the sampling period determined, on a subsequent film thickness detection control.

Abstract: An image forming apparatus includes an image bearer including a first image portion to bear a first toner image, a second image portion to bear a second toner image, and a non-image portion to bear an adjustment pattern. A transferor forms a transfer nip with the image bearer. A controller controls the power source to output an image bias as a transfer bias to transfer the first toner image and the second toner image onto a first recording medium and a second recording medium, respectively, in the transfer nip when the first image portion and the second image portion pass through the transfer nip and output a non-image bias as the transfer bias when the non-image portion passes through the transfer nip. The controller performs a constant current control on the image bias and performs a constant voltage control when the image bias switches to the non-image bias.

Abstract: An image forming apparatus includes an image bearer including a first image portion to bear a first toner image, a second image portion to bear a second toner image, and a non-image portion to bear an adjustment pattern. A transferor forms a transfer nip with the image bearer. A controller controls the power source to output an image bias as a transfer bias to transfer the first toner image and the second toner image onto a first recording medium and a second recording medium, respectively, in the transfer nip when the first image portion and the second image portion pass through the transfer nip and output a non-image bias as the transfer bias when the non-image portion passes through the transfer nip. The controller performs a constant current control on the image bias and performs a constant voltage control when the image bias switches to the non-image bias.

Abstract: An image forming apparatus includes an image bearer, a transfer member, and a power source. The image bearer includes a plurality of layers. The transfer member forms a transfer nip between the image bearer and the transfer member. The power source outputs a transfer bias to transfer a toner image from the image bearer onto a recording sheet in the transfer nip. The transfer bias alternates between a transfer-side bias that causes the toner image to move from the image bearer to the recording sheet, and an opposite-side bias different from the transfer-side bias. A duty ratio of a time period, during which the opposite-side bias is output, relative to one cycle of a waveform, is greater than 50%.

Abstract: A power supply controlling device includes: a direct-current power supply configured to output a direct-current voltage; an alternating-current power supply configured to output one selected from between a superimposed voltage obtained by superimposing an alternating-current voltage onto the direct-current voltage and the direct-current voltage; a bypass capacitor configured to partially store therein an output from the alternating-current power supply and configured to, when the direct-current voltage is output from the direct-current power supply while no electric charge is stored therein, store therein a second direct current being a part of a first direct current output from the direct-current power supply in conjunction with the output of the direct-current voltage; and a power supply controlling unit configured to cause the direct-current power supply to control a level of the direct-current voltage based on a target value for the first direct current and a value indicating the second direct current.

Abstract: A power supply controlling device includes: a direct-current power supply configured to output a direct-current voltage; an alternating-current power supply configured to output one selected from between a superimposed voltage obtained by superimposing an alternating-current voltage onto the direct-current voltage and the direct-current voltage; a bypass capacitor configured to partially store therein an output from the alternating-current power supply and configured to, when the direct-current voltage is output from the direct-current power supply while no electric charge is stored therein, store therein a second direct current being a part of a first direct current output from the direct-current power supply in conjunction with the output of the direct-current voltage; and a power supply controlling unit configured to cause the direct-current power supply to control a level of the direct-current voltage based on a target value for the first direct current and a value indicating the second direct current.

Abstract: An image forming apparatus includes an image bearer, a transfer member, and a power source. The image bearer includes a plurality of layers. The transfer member forms a transfer nip between the image bearer and the transfer member. The power source outputs a transfer bias to transfer a toner image from the image bearer onto a recording sheet in the transfer nip. The transfer bias alternates between a transfer-side bias that causes the toner image to move from the image bearer to the recording sheet, and an opposite-side bias different from the transfer-side bias. A duty ratio of a time period, during which the opposite-side bias is output, relative to one cycle of a waveform, is greater than 50%.

Abstract: An image forming apparatus includes an image bearer, a transfer member, and a power source. The image bearer includes a plurality of layers. The transfer member forms a transfer nip between the image bearer and the transfer member. The power source outputs a transfer bias to transfer a toner image from the image bearer onto a recording sheet in the transfer nip. The transfer bias alternates between a transfer-side bias that causes the toner image to move from the image bearer to the recording sheet, and an opposite-side bias different from the transfer-side bias. A duty ratio of a time period, during which the opposite-side bias is output, relative to one cycle of a waveform, is greater than 50%.

Abstract: An image forming apparatus includes an image bearer, a transfer member, and a power source. The image bearer includes a plurality of layers. The transfer member forms a transfer nip between the image bearer and the transfer member. The power source outputs a transfer bias to transfer a toner image from the image bearer onto a recording sheet in the transfer nip. The transfer bias alternates between a transfer-side bias that causes the toner image to move from the image bearer to the recording sheet, and an opposite-side bias different from the transfer-side bias. A duty ratio of a time period, during which the opposite-side bias is output, relative to one cycle of a waveform, is greater than 50%.

Abstract: In an embodiment, a fixing device includes: a fixing member that revolves in a circumferential direction in a heated state and transfers heat to a recording medium that is brought into contact with an outer circumferential face thereof; a temperature detecting unit that detects a temperature of the outer circumferential face of the fixing member; and a circumferential-direction position adjusting unit that adjusts a circumferential-direction position of the fixing member such that the recording medium is brought into contact with a high temperature portion out of the high-temperature portion of the outer circumferential face of the fixing member of which temperature detected by the temperature detecting unit is relatively high and a low-temperature portion of which temperature detected by the temperature detecting unit is relatively low.

Abstract: In an embodiment, a fixing device includes: a fixing member that revolves in a circumferential direction in a heated state and transfers heat to a recording medium that is brought into contact with an outer circumferential face thereof; a temperature detecting unit that detects a temperature of the outer circumferential face of the fixing member; and a circumferential-direction position adjusting unit that adjusts a circumferential-direction position of the fixing member such that the recording medium is brought into contact with a high temperature portion out of the high-temperature portion of the outer circumferential face of the fixing member of which temperature detected by the temperature detecting unit is relatively high and a low-temperature portion of which temperature detected by the temperature detecting unit is relatively low.